Starting From Scratch

Transcript

Starting from scratch Whether you are starting a new garden, or re-establishing an old one, this fact sheet will help you ‘start from scratch’ by helping you to prepare your soil, choose appropriate plants and design a garden that will be suitable for Canberra’s climate. Planning a garden can be a difficult and time consuming task. Many people don’t even think about what they want in the long-term and just choose plants to fill a gap or cover up the soil. Many people plant the wrong plant in the wrong place and end up using more water than they need to, just to keep the garden alive. It’s easy to become discouraged and give up on gardening if you see your plants wither and die. However, with a little forward planning you can save time, effort, money and water by designing a garden around your likes and dislikes, the local environment and your family’s needs. When establishing a new garden, or redeveloping an old one, start by looking at what type of garden you want. Are you planting natives or planning a cottage style garden? Or would you like a formal garden of hedges, stately trees and flowering bulbs and annuals? This decision will determine the type of soil and the nutrients you need to provide your plants as well as how the soil should be prepared for planting. Before buying any plants draw a sketch or plan of where you’d like trees and garden beds, where the kids would like to play or where you’d like to stretch out with a book. Look at gardening web sites or magazines to help you decide on a style. While in your garden take careful note of where the sun is, where the wind comes from and where there is natural shade. Soil Soil is the most important part of a successful garden. The type and depth of soil, how much nutrient and organic material it contains, whether it is compacted and many other factors all contribute to the health and vigour of your plants. The way water can be absorbed into the soil is the most important part. Your soil type and condition will determine: • how much water it can hold; • how long it can retain water at the root zone; • how fast water can be absorbed when you irrigate; and • how much water you need to give your plants in addition to rainfall. Water will be wasted on poor condition soil because it runs off the soil surface or drains below the plant root zone. The two most important steps you can take to ensure that you provide just enough water for your plants to stay healthy are to: • understand your soil type, structure and depth; and • improve your soil so that water infiltrates into the root zone, and is held there. Preparing your soil Before you plant, it is important to lay out garden beds and prepare your soil. Depending on your garden style you might like to design beds for your plants that are raised and contain improved soil, incorporate rocks and other features to improve shelter and drainage, or simply plant into the Plant choices The final component of a successful garden is plant choice. The type of plants you choose depends on your preferred garden style, the soil you have, how sheltered your garden is and how much effort you want to expend on your garden. Water use is also a key consideration and many people are turning to waterwise plants for a vigorous, low water-use garden. The best places to find out about plant choices are garden centres and nurseries. The staff will give you advice about what plants fit with your plan and how much care they will need. You can also use the Canberra Plant Selector on the ACTSmart web site. underlying soil to cut costs and work. Whatever choice you make, two characteristics of your soil are essential for good garden health: • drainage; and • organic material. Good drainage requires a relatively deep, crumbly and uncompacted soil. Adding organic material assists both with drainage and water-holding capacity. It also provides plants with essential nutrients. Once your soil is improved mulch can help keep soils moist. However, be careful that you don’t apply the mulch too thickly. More than 75 mm of mulch can remove water and nutrient from the soil. The information you need to prepare your soil can be found in the Importance of Soil Fact Sheet. Changing your microclimate The climate in Canberra is hot and dry in summer and cold and frosty in winter. Both extremes can make gardening very difficult. It is therefore important to understand the climate in your garden, or your microclimate. Garden microclimates can be used to improve the success of your plantings by taking advantage of the varying conditions. You can use hot sunny spots to grow succulents and moist shady locations for ferns. You can also alter your microclimate by using shady trees, pergolas or windbreaks such as hedges. When planning a garden take note of where the sun is at various times of the day and the areas that are sheltered when hot winds are blowing. Think about whether a clever tree planting or a well positioned windbreak might lessen the impact of the sun or wind. Make note of the sheltered and unprotected zones in your garden and seek advice from your nursery about appropriate plant choices for each area to suit your overall garden plans. Consider staggering your planting by establishing the upper storey with shade trees first and then planting underneath in consecutive seasons. By taking care when planning your garden, carefully altering the microclimate and selecting your plants wisely, you can improve the success of your garden and also save water. See the Microclimate Fact Sheet for more details. MORE INFORMATION Website: www.actsmart.act.gov.au Ph: 13 22 81 Email: [email protected] Printed on 100% recycled paper Jan 2012 WRG-A 11/1716 2 Best practice guidelines for a water efficient garden These guidelines will help you create and maintain water efficient landscapes in the Canberra region. They provide a step by step checklist to help you incorporate the findings of the WaterRight Gardens Webtool into your garden. In the Canberra region, water efficient gardens often have a number of key things in common: • Uncompacted, soil to a depth of 250 mm, with plenty of organic material. • Good protection from prevailing summer wind and sun. • The right plants in the right locations, in particular hardy plants in exposed, sunny locations. • Mulch and areas of groundcover plants. • Efficient methods of watering, which take rainfall and the season into account in the watering schedule. • Sources, other than tap water, for irrigation. SOIL Soil is a crucial element in most water efficient gardens. It provides the necessary water and nutrients to keep plants healthy. Tips to create a good, deep soil: • Ensure you have enough topsoil, at least 250 mm, with a good structure. Raised and mounded garden beds can help create these conditions. • You can improve poorly structured and compacted soil by adding decomposed organic matter, by working the soil or by aerating your soil with a fork. • • • • • Gypsum or clay-breaker can be worked through compacted clay soils, to improve drainage, water penetration and nutrient availability. Avoid adding uncomposted woody material to your soil. Apply organic matter regularly, as it breaks down. It may take several years to improve a poorly structured soil. Don’t dig clay soil when it is too wet – you’ll only add to the compaction. Be sure to incorporate the original soil into plantings, and dig deep, wide holes when planting trees and shrubs to avoid waterlogging. MICROCLIMATE Different microclimates provide different growing conditions for plants. Matching plants to the conditions they require is a major step towards creating a healthy and waterwise garden. Sun and shade The position of the sun in different seasons and the patterns of sun and shade at different times of the day will have a major impact on plant choice and water use. • Generally the northern and western sides of your house will be sunnier, warmer and more exposed to the elements, particularly summer winds, making this the best place for tough low water use plants. North facing slopes often receive more direct sunlight and summer wind than south facing slopes. • • • • Buildings and hard surfaces • Buildings, walls, fences and other structures can radiate heat, creating garden hot spots that may require additional watering. Alternatively, they may block the sun, creating areas of shadow that suit shade tolerant plants and less watering. • House eaves may limit the amount of rainfall that a garden receives. This can create a dry microclimate, particularly on the northern (hot) side of the house. Use very low water-use plants, such as cacti, in these areas. • Large areas of hard surfaces can create hot spots that require additional water. Front gardens are often affected by the road or a driveway. Choose light coloured paving (and walls) that absorb less heat to minimise this effect. • By making paved areas more permeable, rain can seep into soil for nearby plant roots. • Try to make paths from organic material such as woodchips or bark mulch rather than hard materials. Create shade through the design of your garden. Use trees, shrubs, windbreaks, climbing plants, pergolas or screens to make the garden cooler and need less water. Large trees provide their own shady microclimate. Deciduous trees can be useful on the north side of the house to provide summer shade, but let in winter light in. High levels of shade often occur on the southern or south-eastern sides of a house. If you have high water-use plants, this is the area for to plant them. Use shade tolerant plants in these areas. Monitor the growth of trees. Prune trees to let more light into your house or onto your sun loving plants. Wind • Create windbreaks on the northern and western sides of your garden to provide protection from hot, dry winds. Windbreaks can include lattice, screens, shade cloth or pergolas. • Use living windbreaks such as hedges or screening plants to protect your garden, and create shade and privacy. • Windbreaks should act as a filter rather than a barrier. A solid barrier will create turbulence behind the windbreak. • If you can’t create windbreaks, ask your local nursery about plants that tolerate windy conditions. PLANTS By placing plants in good, deep soil and in the best microclimate to meet their growing needs, you can create a waterwise garden. • Wherever possible, use water efficient plants— indicated by ‘one drop’ in the Canberra Plant Selector tool. When buying plants, ask nursery staff which ones use less water. • Always group plants with similar water requirements together in separate watering zones or green areas. • Plant trees and shrubs where they create natural shade and windbreaks to reduce evaporation of higher water use plants. • Plant moisture loving plants in low lying areas, or at the base of garden slopes. • High water use plants including most vegetables, fruit trees and flowering annuals, require a sunny position. Try to use wind breaks around them to use water more efficiently. • Remember to keep weeds under control as they compete with garden plants for water and nutrients. Slopes • The topography and slope of your block will affect drainage patterns, and may cause wet and dry areas. This affects planting schemes and irrigation regimes in different areas. • You can turn slopes to your advantage by placing high water-use plants in garden beds at the bottom of slopes. • By contouring a garden, you can redirect runoff from paths or driveways to where it is needed – in your lawn areas or garden beds. • Terracing can help prevent water wastage on sloping blocks. • Try to avoid planting lawn on slopes as this can lead to water loss from runoff. 2 mulch Many organic and inorganic materials can be used as mulch. Organic mulches are the most popular because they improve soil structure and add nutrients to the soil as they decompose. • Top up organic mulches regularly, as they break down relatively quickly. • The best organic mulches are made of coarse material that enables rain or irrigation water to penetrate through to the soil. • It is best to spread mulch thickly—50 to 75 mm deep for most organic mulches. However it is critical not to lay mulch too deeply. • Apply mulch to wet soil that has been freshly weeded. • Check the mulch regularly for compaction, and loosen it to ensure water can get through. • Never let organic mulch sit against plant trunks and stems. • • monitor weather reports and use old sheets, shade cloth or upturned flower pots to cover sensitive plants if frost is predicted; and regular spraying of the foliage of your plants with a seaweed based soluble fertiliser can provide increased resistance to frost. how to water efficiently An efficient irrigation method and schedule is the key to saving water and ensuring your garden’s health. Understanding how to water, using techniques such as drip irrigation and water pulsing will ensure water is used efficiently in your garden. • Only apply the minimum amount of water needed to keep your plants healthy. • Try to ensure the water infiltrates the root zone without any runoff and distribute the water evenly. • If required, pulse watering events so as to avoid runoff. This technique means that you apply water on small parts of each Green Area, watering only until it cannot be absorbed by the soil. This is evident when water either pools on the surface, or runs away. Once this happens, stop watering that spot and move on, returning when the water has all been absorbed. You can then continue watering until the garden’s needs are satisfied, according to your irrigation schedule. • Sandy loam and loamy sand soils, such as improved clays or purchased garden mixes, hold a lot of water, needing less frequent watering. • Aim to apply the same amount of water each time, but change the period between watering to suit the season and weather. This is known as irrigation scheduling or irrigation frequency. The WaterRight Gardens Webtool will provide an irrigation schedule for your garden and lawn areas. • Remember to incorporate natural rainfall into your irrigation schedule. Buy a rain gauge and place it in your garden. Defer watering if you get more rain than your soil can hold. The WaterRight Garden Webtool will help you with this. • When establishing plants, make sure you give thorough soakings that encourage deeper roots, rather than light surface waterings. • Whichever way you water your garden and lawns, ensure you follow the guidelines in the Irrigation methods Fact Sheet. groundcover Covering as much of the soil as possible is critical in a successful Canberra garden and groundcover plants (living mulch) are an ideal alternative or addition to your garden mulch. They protect the soil and other plant roots from the sun and assist in keeping moisture in the soil. • Groundcovers can include creeping plants, densely planted perennials, ferns and other plant species. • They reduce the rate of water evaporating from the soil. FRost Frost is a regular event in the colder months, which can have serious impacts on Canberra gardens. Frost will burn the foliage of sensitive plants, damage new shoots and kill seedlings or otherwise stressed plants. Some tips that will help your garden survive frosts include: • choose plants for your garden that are frost tolerant; • avoid planting sensitive species in low lying areas or frost hollows; • avoid planting new seedlings during the colder months; • plant sensitive species adjacent to walls, under eaves or beneath the canopy of trees; 3 container plants Potted plants, even drought tolerant ones, require regular watering as they have less soil to draw water from. The following tips will help you create water efficient container plants. • Larger pots are generally more water efficient than small pots. • Group pots together to help keep them cooler. Group them according to their watering needs, especially if you are watering them with an irrigation system. • Use a premium quality potting mix and add hydrated water crystals around the roots of new plantings. • Mulch the surface of the potting mix. • If the potting mix becomes water repellent, treat with a soil wetter, or soak the pot in a larger container of water and soil wetting agent until it stops bubbling. • Allow the top 2 cm of potting mix to dry out between waterings to avoid overwatering your plants. • Unglazed terracotta pots are very porous, absorbing water readily. Line them with plastic, ensuring you cut out drainage holes, or treat the inside of the pot with a sealant. • Protect hanging baskets from drying winds. • Always check to ensure you are watering at times permitted by current water restrictions. Visit www.actew.com.au or call 6248 3131 for the latest information. • Where possible, try to use alternative water sources for your garden watering, such as rainwater, greywater or bore water. To work out the best water supply for your garden, check the Sources of water for your garden Fact Sheet. lawns Lawn plays a key aesthetic and recreational role in gardens and can have a place in waterwise garden design. • The better the soil beneath your lawn, the deeper the roots and the less water needed. • Refrain from over-watering your lawn and let it brown off during extended dry periods, you will discover it has an excellent capacity to recover after rain. • If you feel you must water your lawn, water infrequently but deeply. Monitor if water is penetrating the soil during watering, and use pulsed watering to ensure efficient water use. See the Irrigation methods Fact Sheet. • Water your lawn if it is showing signs of stress, such as losing colour (in summer) or if the grass wilts or leaf blades roll or fold in half lengthways. Another way to tell if your lawn needs watering is to step on it. If footprints remain visible, it needs watering. • Don’t cut lawn too short. The ideal height for lawn is around 50 mm. If your lawn becomes particularly long it is important to bring it back to 50 mm gradually. More severe cutting can stress the grass. Cut one-third of the grass blade each time you mow. Longer lawn is more resilient to foot traffic, looks lusher and helps retain moisture in the soil. • Leave clippings to sit on the lawn as mulch. • Aerate your lawn regularly to ensure that rain or irrigation penetrates efficiently and evenly. Treat with a soil wetting agent if required. Constant change Remember, your garden’s microclimate may change with time and as plants grow or are removed. As your garden changes, revisit the WaterRight Gardens Webtool regularly, to ensure you are using the correct watering schedule. MORE INFORMATION Website: www.actsmart.act.gov.au Ph: 13 22 81 Email: [email protected] Printed on 100% recycled paper Jan 2012 WRG-B 11/1716 4 Mulch Mulch provides a protective covering for the soil—making it an important tool for creating a waterwise garden. Mulch reduces water loss from the soil by decreasing evaporation. It helps keep soil cool in summer, slows water runoff, inhibits weeds and can improve soil quality. Many organic and inorganic materials can be used as mulch. Sugar cane is a popular bagged mulch. Spread it loosely to allow water penetration and loosen it if it becomes compacted. organic mulches Organic mulches are the most popular because they can improve soil structure and add nutrients to the soil as they decompose. Because they do break down they should be topped up regularly. Avoid using highly nutritious organic mulch on garden beds containing drought tolerant plants as it may over-stimulate them and reduce their drought tolerance. This type of mulch is best suited to cottage gardens and perennial beds. The best organic mulches are made up of coarse material that allows rain or irrigation water to penetrate through to the soil. Other forms of straw can be used and can look good on vegetable gardens, but may contain weed seeds. Try to avoid mulch with too much fine material (such as sawdust) as it will absorb too much water. Composted and aged manure are generally regarded as soil improvers (when dug into the soil) but can also be spread on the surface as mulch. Fresh grass clippings can be used, but are best mixed with leaves, compost or twigs and left to decompose before use. Once broken down they should be spread thinly (30 mm) to avoid compaction and heat build up. When applied too thickly they can become water repellent. Grass clippings can be left on the lawn as mulch. Fallen leaves can also become compacted and decompose slowly. They are best composted first or put through a garden shredder. They can also be run over with a lawn mower or mixed with coarser materials. Avoid Casuarina and pine needles as they can be acidic and often lead to water repellency. Tea tree mulch blends in well with native gardens. Lucerne hay and pea straw decay quickly and provide nutrients to the soil. They are very good around roses, perennials and flower beds, but may contain weed seeds. Wood chips and tree bark look neat and save water, but they decay slowly, provide few nutrients and can deplete garden soils of nitrogen (nitrogen drawdown). If applied too thickly they can also stop water reaching the soil. With wood chips it is therefore essential that they be applied no thicker than 75 mm deep. Many landscapers apply them thickly to reduce maintenance. However these gardens seldom thrive and require much more water to remain healthy. If you use wood chips or tree bark, add some nitrogen-rich fertiliser or organic matter such as lucerne, manure, blood and bone or compost to the soil, before mulching. Composted horticulture bark, usually bought in bulk from landscape suppliers, is coarse, doesn’t create nitrogen drawdown and looks good. Shredded newspaper can also be used as mulch, again best underneath organic material. Avoid thick layers of whole newspapers because these will prevent water and air reaching the soil, causing nitrogen drawdown. Groundcover plants Groundcover plants act as ‘living mulch’. They reduce water loss from the soil by providing shade. These are a great option for Canberra gardens. Refer to the Canberra Plant Selector on the ACTSmart website for groundcover plants suitable for your garden. INORGANIC MULCHES Gravel, scoria, pebbles, crushed rock and other inorganic materials can be used as mulch. They are non-flammable and therefore useful in areas where it is important to minimise fire risk (e.g. against your house). However they may gather leaves and soil debris which can be difficult to remove. Woven plastic materials such as weedmat can be used to provide better weed control. They need to be anchored in place and look better covered with organic mulch. A drip system must be installed underneath the weedmat if it is used on an area that requires irrigation. Ordinary plastic sheeting should not be used as mulch. It prevents air and water passing into the soil and can greatly increase soil temperature and cook plant roots. How to apply mulch • Remove all weeds before applying. • Break up the soil surface and water well. • Spread the mulch evenly across the soil surface—up to 75 mm deep for most organic mulches. • Never mulch greater than 75 mm in depth. If mulch is too deep, it can reduce soil water absorption and can stop water reaching plant roots. • Keep organic mulch away from trunks and stems to avoid collar rot. maintaining mulch • Regularly pull apart mulch after watering to check if water is getting into the soil beneath. • Check that mulch is not becoming too compacted, and loosen it if necessary to ensure water can penetrate. • If mulch becomes too dry and repels water, rake it to break the surface crust, before watering. This is most likely to occur with small particle mulches. • If weeds appear, remove or spray them before they can flower and seed. • When removing weeds, be careful not to bring soil to the surface as this can encourage more weed growth. MORE INFORMATION Website: www.actsmart.act.gov.au Ph: 13 22 81 Email: [email protected] Printed on 100% recycled paper Jan 2012 WRG-C 11/1716 Irrigation methods Many gardeners use a combination of irrigation methods, including fixed irrigation systems, hand-held hoses and buckets or watering cans. Water restrictions may limit you to a particular method, and will override the information in this Fact Sheet and the WaterRight Gardens Webtool. Clay soil has a slow infiltration rate and runoff occurs if you deliver water too quickly. You may need to deliver water intermittently, giving the soil enough time to absorb a small amount of water before applying more. This is known as cyclic or pulse watering. How to water efficiently Always use water efficiently, only applying the required amount to keep your plants healthy. To water efficiently, try to ensure the water infiltrates the root zone without any runoff, and distribute the water evenly. Apply the same amount of water each time, but change the period between waterings to suit the season and weather. This is known as irrigation scheduling or irrigation frequency. Cyclic watering or water pulsing Cyclic watering is an efficient watering method that keeps your garden healthy with minimal water usage. This method does not cause excessive pooling or run-off and helps water to penetrate the soil. You can apply the following principles of cyclic watering to all watering methods. How much water you apply and how often you water is influenced by: • your site slope; • soil type; • planting scheme; and • microclimate. The impact of these is explained in the other Fact Sheets. To maximise the efficiency of your irrigation system it is particularly important to understand your soil type and the rate that it absorbs water (infiltration rate). Sandy soil or sandy loam has a fast infiltration rate, as long as it isn’t water repellent. It needs frequent watering with smaller amounts to prevent water being wasted by draining away from the root zone. Water the area until pooling or run-off just begins (often five minutes is enough) and then turn the water off. Wait until water has soaked into the soil and then repeat the cycle. In between watering cycles, dig down to see how far the water has penetrated the soil. Repeat the cycle until the water reaches the depth of the root zone (about 300 mm) or until the total time spent watering conforms to your watering instructions, provided in the WaterRight Garden Webtool. Watering deeply and infrequently encourages a deep, healthy root system. fixed irrigation systems A well designed, operated and maintained automatic irrigation system is often the most time and water efficient way to apply water. Even the simplest system with a tap timer can be effective. While you can design and install your own automatic system, if the design is not appropriate for your garden or you do not know how much water your system delivers when you operate it, you could be wasting water. If you decide to install an irrigation system yourself, seek advice on the installation and operation from a qualified irrigation stockist. In-line drip tubing is ideal for high density plantings, vegetable gardens and around groups of plants or larger shrubs and trees. Most products are available in 1.6 to 2 litres per hour (LPH). Generally the emitters are spaced at 300 mm, but wider spacing is sometimes used. For large blocks or sloped sites, pressure compensated emitters should be used. Some points to note: • Ensure your system meets any local regulations, especially backflow prevention regulations. • Ensure the system waters evenly around the root zone – avoid wet and dry spots. • Ensure sloping areas are adequately watered without flooding other areas. • Use separate watering zones for areas of the garden that have different watering requirements, e.g. garden beds, vegetable gardens or lawn areas. • Once you have different zones you may need an electronic controller. • Use soil or rain sensors that override electronic controllers so you only water when the garden needs to be watered. • Don’t mix drippers with different application rates on the same irrigation line. On-line drippers are available in 2 LPH, 4 LPH and 8 LPH. The 2 LPH emitters are generally best suited for compacted soil types that occur throughout Canberra. This lower application rate will allow the water to move deeper into the root zone, reducing the risk of runoff or pooling. To design a drip irrigation system that is suitable for your garden, talk to your local irrigation professional. Things to consider for drip irrigation: • Systems must be site and soil specific and are best if professionally designed and installed. • Accessories such as filters, flushing valves and pressure regulation valves may be needed for satisfactory operation (especially in larger gardens). • Systems require regular checks for evenness of watering, blockages and leaks. • It can be easy to forget the system is on if it is manually operated—install a flag indicator that pops up when the water is flowing. • Be careful when digging in the garden to avoid puncturing or cutting driplines. • Drip systems may waste water on sandy soil where water drains straight through. • For lawns, drip irrigation is expensive to install, can be pierced during operation or laid too deeply (below the root zone). Where there is heavy foot traffic, soil can become compacted and block emitters. • Fixed spacing of in-line drippers will not be suitable for every style of garden. Drip irrigation Drip irrigation can be an efficient and effective watering method for use in Canberra. A correctly designed and installed system can save water provided it is used correctly. Some advantages of drip irrigation: • It enables water to flow at low volumes and low pressure and can be set to provide effective cyclic or pulse watering. This allows time for the water to infiltrate the soil and therefore reduces the chance of runoff. • Water is delivered directly to the soil surface (under the mulch) and not to leaves. This limits evaporation, avoids wind drift and can reduce the occurrence of fungal infections and avoids water loss from wind drift. • When combined with a rainwater tank, drip irrigation can free you from water restrictions, allowing you to respond quickly to your garden’s water needs. Weeping hose Weeping (or seeping) hose is usually made of black recycled tyre rubber and is designed to release water into the soil under low water pressure. The required water pressure depends on the length of the hose, and uneven water distribution may result. Weeping hose can be buried in the soil, or laid on top of the soil and covered with mulch. Weeping hose is regarded as drip irrigation under the ACT’s Temporary Water Restrictions Scheme. These hoses are not There are two types of drip systems: • ‘in-line’—tubing with in-built dripper holes at regular spacings; and • ‘on-line’—soft poly pipe into which you insert drippers where you require them. 2 Hand-held hosing Using a hand-held hose for watering allows you to very specifically target your watering volumes and frequency to meet the needs of your garden. UV stabilized and may rot or split easily. They should not be confused with the green plastic type of soaker hoses, which are not regarded as drip irrigation under the ACT’s Temporary Water Restrictions Scheme. However, if not performed properly, hand-held hosing will waste water, and could also be ineffective in delivering the correct amount of water to meet your plants’ needs. Sprinkler systems Under the ACT’s Temporary Water Restrictions Scheme, the use of sprinklers is more restricted than the use of drip systems and hand watering. One of the challenges with hand-held hosing is that it is difficult to know just how much water you have applied and whether you have applied it evenly. Become familiar with how long you need to water each area of you garden by digging into the root zone after a watering event to see if the water has reached the required depth. Adjust your watering time according to you observations. Fixed sprinkler systems that operate at relatively low pressures and use low volume spray nozzles (micro-sprays/ micro-sprinklers) can disperse water in an array of shapes and spray patterns. A properly designed fixed sprinkler system will have the spray heads set up and spaced correctly to: • provide even water distribution; • minimise evaporation and wind drift; and • avoid overspray onto hard surfaces, buildings and fences. Hand-held hosing also takes time and if you are short of time there is a risk that you will water too lightly for the water to reach the root zone of your plants. This will result in shallow-rooted plants that are less able to survive dry conditions. The system should also be programmed to suit the site specific planting scheme and the infiltration rate of the soil. It is important to use coarse mulch so the spray can penetrate to the soil. Some tips for watering efficiently and effectively with a hand-held hose: • Always use a trigger nozzle or water wand when applying water with your hose. You should apply a gentle stream at a rate that allows the water to penetrate into the soil and the root zone, without causing runoff. • Only apply the amount of water that your plants need, when they need it. • Schedule your hosing in the same way as a fixed irrigation system—apply the same amount of water each time you irrigate and alter the intervals between watering events according to weather conditions and seasons. • Adjust your watering according to the amount of rain that has fallen (or is predicted) and the temperature. • Use pulse or cyclic watering principles. • Ensure an even distribution of water across similar plant types. • Apply water to the soil and root zone (not the leaves). If you are watering with a moveable sprinkler on a garden hose, don’t forget to move it around your garden to ensure even watering. As the potential to ‘set and forget’ these sprinklers is high, it is recommended that you use a tap timer to automatically turn off the sprinkler after the required watering time. As plant growth can block or divert water, you may need to add more spray heads as your plants grow. Irrigating lawn Lawn irrigation is restricted in certain stages of the ACT’s Temporary Water Restrictions Scheme. If you are unsure about whether you can irrigate your lawn, contact the ACTEW Water Conservation Office on 6248 3131. High pressure pop-up sprinkler systems with the right sprays are suitable for lawn irrigation. There is a wide range of pop-up heights and nozzle configurations for small spaces and awkward lawn shapes. The critical element in lawn irrigation is careful placement of sprayers to get even water distribution. Triangular rather than square grids are usually recommended. 3 Buckets and watering cans Using buckets or watering cans as a sole irrigation method requires manual labour and is best suited for small garden beds or potted plants close to the tap. Watering cans are better than buckets, since they make it easier to apply smaller quantities of water at a slower infiltration rate. MORE INFORMATION Website: www.actsmart.act.gov.au Ph: 13 22 81 Email: [email protected] Printed on 100% recycled paper Jan 2012 WRG-D 11/1716 4 Microclimate The wind, temperature and rainfall of your area will largely dictate what plants will thrive in your garden. In Canberra, there can be significant variations in the climate within your yard, called microclimate. Accurately assessing your garden’s microclimate will help you water effectively and plan your waterwise garden. coping with climate Canberra gardeners have to contend with a relatively dry, continental climate with warm to hot summers and cool to cold winters (including frost). Additionally, prevailing winds in Canberra’s seasonal climate vary and will have very different effects on your garden. Summer winds in Canberra are generally hot, northerly and westerly winds. While temperature and rainfall have an obvious impact on your plant choice and water use, you should also be aware of the effect of your garden’s microclimate. The aspect, amount of sun and shade you get in your garden, the prevailing winds and the slope together create your microclimate. Your garden’s microclimate is moderated by: • buildings; • walls; • fences; • structures; • the placement of hard surfaces such as paving, paths or roads that may radiate extra heat; • trees; • shrubs; and • windbreaks. right plant right place You can make your garden more water efficient by understanding: • how your garden features create microclimates; • how to use your garden features to your advantage; and • how to modify your garden features if necessary. Each microclimate provides different growing conditions for plants. Matching plants to the conditions they require is a major step towards creating a healthy and waterwise garden. Plants that are matched with climates, and with the microclimates that suit them, will need less water and maintenance, grow better and suffer less stress. site ASPECT It is critical to know which direction your garden faces, especially which way is north, because that’s the direction the sun comes from. The position of the sun in different seasons and the patterns of sun and shade at different times of the day will have a major impact on plant choice and water use. A sunny aspect is useful if you want to grow plants that require full sunlight, especially vegetables and fruit trees. However it may also mean that you use large quantities of water. Drought tolerant plants are a good choice for a sunny aspect. You can modify the impact of aspect, but generally the northern side of your house will be sunnier, warmer and more exposed to the elements. So the best place for most low water-use plants is the northern side of your house. Also, an exposed western side will get the hot afternoon sun, creating high water demand unless you plant arid zone plants. using shade Design your garden to create natural shade, so the garden will be cooler and need less water, by: • using trees, shrubs, windbreaks, climbing plants, pergolas and screens to provide shade for the garden and outdoor living areas; • planting large trees that provide their own shady microclimate. Deciduous trees can be useful on the north side of the house to provide summer shade and will let in winter light and warmth; and • planting high water-use and/or shade or semi-shade tolerant plants on the south or south-eastern side of the house. You will probably need to apply less water in this area than you use in your north facing area, as it is often more shaded and moist. If you can’t moderate the wind, choose plants that tolerate the conditions. Plants with tough, hard leaves or silvery leaves often tolerate wind. Most Canberra area native plants can tolerate the effects of both heat and wind exposure and are worth considering if you want to create a garden suitable to the local conditions. WIND Canberra’s climate varies from season to season, particularly with respect to the prevailing winds. These winds have an impact on your garden’s water needs. Summer’s hot, dry westerly and northerly winds reduce humidity and greatly increase water loss from leaves due to transpiration and from soil due to evaporation. North and west facing slopes receive more direct sunlight and are more affected by summer winds than south facing slopes. South facing slopes are more affected by cold winter southerly winds. slopes The topography and slope of your block will influence the microclimate by affecting drainage patterns. This can cause wet and dry spots, and may influence your planting schemes and irrigation patterns. In Canberra, slopes facing into the seasonal prevailing winds can also increase exposure to strong winds and this needs to be taken into account in garden planning. You can turn slopes to your advantage by placing higher water-use plants in garden beds at the bottom of sheltered slopes. On steep exposed slopes, use low water-use plants, including appropriate natives, succulents or other tough, waxy leafed species. The rate of transpiration rises with an increase in temperature, wind speed and a decrease in humidity. Plants wilt much faster on hot days, especially when the hot, dry summer winds are blowing. You can deliberately contour a garden to redirect runoff from paths or driveways to where it is needed, or slope paths towards garden beds. Terracing can help prevent water wastage on sloping blocks. Northerly and westerly aspects can be particularly exposed to these hot, dry summer winds. In winter exposure to the cold southerly winds can mean your garden is vulnerable to frosts and wind burn. Avoid planting lawn on slopes as this can lead to water loss from runoff. Windbreaks can moderate the effect of wind and help reduce your overall water needs. buildings Buildings, walls, fences and other structures affect microclimate in a number of ways: • they can radiate heat to create hot spots that may require additional watering; • they may block the sun to create areas of shadow and shade that require shade tolerant plants and less watering; and • house eaves may create relatively dry spots that don’t receive rain. This can create a hot and dry microclimate (on the north side) suited to cacti and succulents, or cool and dry shade (on the south side) favoured by plants that like cooler conditions. Living windbreaks such as hedges or screening plants protect the garden from wind and create shade and privacy. In Canberra gardens windbreaks to the north and west protect your garden’s plants from hot summer winds. If living windbreaks aren’t possible, use lattice, screens, shadecloth or pergolas to shelter plants. Windbreaks should act as a filter rather than a barrier, since a solid barrier will create an area of turbulence behind the windbreak. 2 hard surfaces Garden beds near paving or driveways that radiate heat will be warmer than those near turf or out in the open. Being near the road often adds heat to front gardens. Large areas of hard surfaces can create hot spots that require additional water. constant change Be aware of changes to the microclimate with the seasons and as plants grow or are removed. Trees that cast increasing shade as they mature may affect your watering regime, or you may have to prune trees to let more light into your house or onto your sun-loving plants. To minimise this effect, choose light coloured paving (and walls) that absorb less heat to minimise this effect. Making paved areas more permeable to allow rain to seep into soil and nearby plant roots can help save water. Make paths from organic material such as woodchips or bark mulch, rather than using hard surfaces. MORE INFORMATION Website: www.actsmart.act.gov.au Ph: 13 22 81 Email: [email protected] groundcoverS Groundcovers can be very useful in keeping weeds under control and reducing the rate of water evaporating from the soil. They also shelter the root system of other plants, allowing a ‘cool root run’ which is very important for the health of many plant species. In Canberra, covering the ground surface is of critical importance in creating waterwise gardens. Groundcovers or ‘green mulches’ can be used to reduce overall water loss from the soil by reducing the impact of wind and sunlight. Printed on 100% recycled paper Jan 2012 WRG-E 11/1716 3 WaterRight Gardens Webtool Canberra Plant Selector Not sure how much water you need to keep your garden looking good? Need help to choose plants suitable for your garden? Find out how plants, your soil, wind, shade and the seasons affect your garden and lawn watering needs. The Canberra Plant Selector enables you to look up information on a range of plants found in Canberra gardens. Enter your garden details into the WaterRight Gardens Webtool to produce watering schedules and other helpful tips. Knowing the growth habit, sun, shade and frost tolerances and the water requirements of plants can help you choose plants suited to your garden, and save water. You can find the WaterRight Gardens Webtool at www.actsmart.act.gov.au or call Canberra Connect 13 22 81 for more information. You can find the Canberra Plant Selector at www.actsmart.act.gov.au or call Canberra Connect 13 22 81 for more information. Plant and lawn requirements Water is added to the soil through rain or irrigation. Plants draw water from the soil through their roots. Although large trees, many plant species in the wild and a few garden plants may be very deep rooted, the feeder roots of the majority of garden plants are up to 300 mm deep. evapotranspiration Water is lost from the soil surface through evaporation and is transpired through the leaves of plants as they grow. Transpiration is essential for plant life, but means plants must constantly replenish their supply of water. The rate of evapotranspiration (water lost from the soil and from plants) increases: • in higher temperatures; • in stronger winds; • when there is low humidity; and • when there is no protective mulch. Water can also run off the surface and drain through the soil past the root zone. Your challenge as a gardener is to manage watering so there is just enough water in the root zone for your plants to stay healthy. Improving your soil, mulching, placing your plants in the right location and using efficient watering practices will help you grow healthy plants using minimal water (see The importance of soil Fact Sheet). The rate at which plants lose water through transpiration varies with the type of plant. Important steps towards saving water include: • using water efficient plants where possible, such as plants adapted to dry conditions and the Canberra area; • • designing your garden so plants with similar water requirements are grouped together into separate watering zones, in appropriate areas; and placing plants in the correct soil and microclimate position to meet their growing needs – the right plants in the right place. plant adaptations to drought Hard, thick or waxy coated leaves are common characteristics of waterwise or drought tolerant plants. Others have small or needle-like leaves and therefore fewer pores or stomata through which water is lost by transpiration. Hairy or felty leaves and silver or grey foliage are other indications of drought tolerance. Some plants have fewer, or virtually no leaves, as in the case of cacti, or fleshy leaves that store water, a characteristic of succulent plants. High water-use plants usually have soft, dark green leaves. Some plants, including many deciduous trees, transpire a lot. However, they have a deep tap root or an extensive root system to draw water from a large volume of soil. Some, but not all Australian natives, and many Mediterranean plants (e.g. lavender and many herbs), South African plants (e.g. proteas) and Californian plants (e.g. Oenothera or evening primrose, Ceanothus) are adapted to dry climates. In Canberra the indigenous or local native plants are largely waterwise, easy care plants that also make an excellent habitat for native birds. Some exotics, including established roses, photinia, nandina and Camellia sasanqua have proven to be relatively tough survivors during extended dry periods. Many new release strappy leafed and architectural plants such as cordylines and yuccas are also relatively drought tolerant. water stress symptoms If you do not provide adequate water for plant growth, at the correct time, you may observe water stress in your garden. The following table can help you identify if you have water stressed plants. Symptom Description Leaf curl Leaves may curl during the day as a defence mechanism against heat and the sun. The leaves should uncurl at night. Wilting Drooping of the leaves and stems occurs in the non-woody parts of the plant. Chlorosis Also known as yellowing of the plant. This predominantly occurs in high water use plants. The tissue turns yellow, and the veins will eventually brown. Leaf abscission This is where the leaves of the plant drop off. Older leaves will fall off first. But leaf abscission is also a natural part of plant growth. Look for other symptoms of water stress as well, such as those in this table. Glossy leaves Plants which have a glossy leaf surface may lose their glossy appearance when water stressed. Wrinkled leaves Leaves of succulents may acquire a wrinkled appearance when water stressed Most established gardens contain a mixture of plants that originate from many different parts of the world and are diverse in their ability to adapt to reduced rainfall. Few of us want to dig up our existing garden and start again from scratch. But when plants need replacing or when planting new garden beds, choose low water-use plants suited to your conditions and group plants with similar water needs together. Some water saving tips: • Plant trees and shrubs where they create shade and windbreaks to reduce evaporation. • Take advantage of sheltered spots to grow more sensitive plants, particularly out of the hot summer winds. • Choose water efficient plants. • New selections of Australian grasses and strappy leafed plants such as Lomandra and Dianella are waterwise plants. • Plant low water-using plants in areas that tend to be dry, such as under eaves. • Put moisture loving plants in a low lying and sheltered area. • Control weeds because they compete with garden plants for water. • Most vegetables are very high water-use plants that need a sunny position. Root vegetables are generally less demanding and can be grouped separately from those that use more water. • Use a windbreak to protect vegetable plots. • Remember to continually improve your soil (see The importance of soil Fact Sheet). garden planning If you are planning a new garden, invest some time in getting to know its aspect and microclimate, particularly its exposure to sun and hot summer northerly and westerly winds, and how these affects plant placement. watering habits and techniques Choosing appropriate plants and improving your soil are two effective ways to decrease the amount of water your garden needs. However using appropriate watering techniques is also very important. Regardless of whether you are using drippers, sprinklers or a hose, timing and directing your watering will allow you to use water efficiently on your garden. The Irrigation methods Fact Sheet will help you choose the best method of watering your garden. Divide the garden into watering zones. Group low water-users together. Medium water-using trees, shrubs and perennials, should be in a different area so they benefit from a thorough soaking, that encourages deeper roots, rather than a light surface watering. Flowering annuals, vegetables and fruit trees are mostly high water users that like plenty of sun. They generally need shorter, more frequent watering. Keep your soil moist Canberra’s clay soils are prone to drying out and, once dry, are very difficult to get water to sink into the soil where the plant roots can use it. You can avoid this problem by ensuring the soil stays moist, by Shade loving, high water-users such as impatiens, hydrangea and fuchsia could be in another watering zone. 2 lawn Lawn plays a key aesthetic and recreational role in gardens. Although you can reduce your lawn area by using permeable paving or planting hardy groundcovers which require less water, turf can still have a place in waterwise garden design. Warm season grasses can survive on relatively infrequent watering if grown in good soil that fosters deep rooting. using groundcover plants, incorporating organic material in soil, introducing structure such as rocks, logs and ponds, and following an effective watering schedule. On hot days, check the moisture content of the soil by pushing your finger or a small trowel into the surface soil. If the soil feels too dry, apply water. Always ensure you comply with any water restrictions. Pulsing your water effort Canberra’s clay soils allow water to soak in at a very slow rate, compared to a sandy soil. If you apply water at a higher rate than the soil’s ability to absorb the water, it will pool and either run off or evaporate before it can reach your plant’s roots. When setting up an irrigation system, you or your installation professional should take this into account and pulse your watering. This means water is applied, then left to soak in before another pulse is delivered. This is also easy to do using a hose or watering can, if you follow a series of simple steps. If you refrain from watering your lawn and let it brown off during extended dry periods, you will discover it has an excellent capacity to recover after rain. If you decide to water your lawn, water infrequently but deeply. This encourages deep root penetration and increased drought tolerance. There are a number of native, drought-tolerant cool-season grasses that could be used to create a native lawn. Consult your local nursery for further information. Tips on watering lawns: • The better the soil beneath your lawn the deeper its roots and the less water is needed to keep it healthy. • Only water your lawn if it is showing signs of stress, such as losing colour (in summer) or if the grass wilts or leaf blades roll or fold in half lengthways. Another way to tell if your lawn needs watering is to step on it. If the footprints remain visible after you have stepped on it, it needs a good soak. • Use cyclic watering techniques if your soil is heavy or compacted. • Don’t mow lawns too short. Mow one-third of the leaf blades each time, keeping blade length to 50 mm. Longer leaf blades shade the root zone, reduce evaporation and assist deep rooting. • Distribute clippings on the lawn as mulch. • Brown patches on grass may suggest a compacted or water repellent soil. Aerate your lawn regularly to ensure that rain or irrigation penetrates efficiently and evenly. You can also treat this problem with soil wetting agent. • Brown patches may also suggest invasion of disease and/or pests such as scarab grub. Consult your local nursery for further information on lawn management. Water small areas of your garden beds (1 m2 patches) until you see water start to run off or pool on the surface. Once this happens, move on to another area, then return and keep watering once the surface water has soaked in. Keep track of how long you spend on each area, to ensure that your garden’s overall watering needs have been satisfied, as per the instructions contained in your WaterRight Gardens Webtool recommendations. By doing this you will ensure that all the water you put on your garden is going where it is needed, into your plants’ root zone. plant selection The Canberra Plant Selector can help you choose garden plants on the basis of their water requirements, and sun, shade and frost tolerances. The Canberra Plant Selector can be found on the ACTSmart web site (www.actsmart.act.gov.au). Plant nurseries and local garden centres are a good source of advice on water efficient plants suitable for gardens in your area. They can also advise on plants that may become weeds. Some plant labels contain information about the water requirements and drought tolerance of plants. 3 • • • • container plants Potted plants, even drought tolerant ones, will require regular watering, as they have less soil to draw water from. Here are some tips to minimise their water use: • Group together pots to help keep them cooler. Group them according to their watering needs, especially if you are watering them with an irrigation system. • Use a quality potting mix. Look for the Australian Standard logo on the bag. A premium mix is advised for most potted plants. The compressed coir or coco peat potting mix bricks that you rehydrate have very good water storing capacity. They can be used on their own or mixed with another potting mix to improve water retention. • Quality potting mixes usually contain some water crystals. Add additional hydrated crystals around the roots of new plantings. • Mulch the surface of the potting mix. Use an organic (e.g. bark or coir) or inorganic (e.g. pebbles or scoria) mulch. • Potting mix can become water repellent. Water running down the insides of the pot and straight out the bottom indicates this. Treat with a soil wetter, or soak the pot in a larger container of water and soil wetting agent added until it stops bubbling. • Larger pots are generally more water efficient than smaller pots. Allow the top 20 mm of potting mix to dry out between waterings. Many potted plants die from overwatering. Unglazed terracotta pots are very porous, absorbing water readily. Line them with plastic, ensuring you cut out drainage holes, or treat the inside of the pot with a sealant. Protect hanging baskets from drying winds. Self watering pots work well if used correctly. Water them from above and allow the water to drain through into the well. Plants draw water from the well by capillary action. Don’t place a very small plant in a very deep container, as the roots will not be strong enough to draw water up from the well. Tall containers require a more open potting mix for capillary action to work. Use a premium potting mix and consider adding some coir to the potting mix. MORE INFORMATION Website: www.actsmart.act.gov.au Ph: 13 22 81 Email: [email protected] Printed on 100% recycled paper Jan 2012 WRG-F 11/1716 4 The importance of soil Soil is the most important element in a water efficient garden. Soil supports plants physically and provides them with water and nutrients. It acts as a reservoir, holding water in pore spaces where it is extracted by plant roots. Canberra soils can be very clayey, subject to compaction and drying out, and can be very difficult to cultivate effectively. By using appropriate methods you can minimise these effects. soils ain’t soils Your soil type and condition will determine: • how much water can be held in the reservoir; • how long it can retain water at the root zone; • how fast water can be absorbed when you irrigate; and • how much water you need to give your plants in addition to rainfall. Canberra soil conditions can vary dramatically between locations and even within a garden. Get to know your soil and its water holding ability by digging gently around the root zone before and after irrigating. Do this a few times and you will get a clearer picture of whether your garden needs watering and if you are applying the right amount of water. Water will be wasted on compacted soil and soil low in organic matter because it runs off the soil surface or drains below the plant root zone. The two most important steps you can take to ensure you provide just enough water for your plants to stay healthy are to: • understand your soil type, structure and depth; and • improve your soil so that water infiltrates into and is held in the root zone. soil types Soil is made up of three main components: • mineral particles; • organic matter; and • air spaces. The most coarse soil particles are sand. Clay particles are the finest, and silt is intermediate in size. The classification of soil into three main textural types – sand, loam and clay – refers to the relative content of these particles. Often soil is a mixture of different mineral particles. In Canberra the majority of soils are clay based, with varying amounts of sand and small pebbles. This variation can affect water penetration. Canberra soils are often compacted and can be subject to extremes of temperature, which dry out the clay. Dry clay soils repel water, reduce water penetration, do not allow plant roots to absorb soil water and make watering ineffective. To create a good gardening soil from Canberra’s naturally-occurring soil, you generally need to improve the soil condition and introduce organic matter. This often means changing the clay based soil to a more free draining clay loam. soil structure Soil structure describes the arrangement of the particles and the pore space between them. Individual particles cluster into aggregates or crumbs that are held together by humus or decomposed organic matter. You can test your soil structure using a spade. Carefully push your spade into the soil using a moderate degree of effort. If your spade penetrates to around 100-200 mm your soil has good structure. Penetration to around 50-100 mm means your soil is slightly compacted or desiccated and has an average structure, and less than 50 mm means that the soil is compacted and has a poor structure. Potential soil improvers include: Compost and/or worm castings – fine compost particles are especially good for sticking to fine sand particles; coarse compost is good for clay soils. Aged animal manure – especially cow manure or chicken manure pellets. Poorly structured soil has no aggregates. In the Canberra heavy clay soils, particles are joined together into a dense mass or hard clod, with few pore spaces. These soils form a crust when they dry. In the extremes of the Canberra climate this can result in a deeply compacted and dry soil with very little water penetration. Plants will struggle to thrive as their water needs will not be satisfied and roots will have difficulty penetrating. Coir or cocopeat – a relatively new product made from compressed coconut fibre that comes in bricks or blocks that you re-hydrate. It absorbs about 10 times its volume in water and has excellent water holding capacity as a soil additive. Mushroom compost – use sparingly. It can be quite alkaline and is not good for acid-loving and native plants. An average soil structure will hold together slightly, but the aggregates will break apart when disturbed by digging, wind or water. Plants will survive, but will not thrive. Composted bark or horticultural grade bark – usually only available from landscape suppliers. A well structured soil will look crumbly with clearly identifiable aggregates or crumbs that do not break apart during digging. These aggregates increase the number of large pores in the soil, allowing air and water to move freely through the soil. Plant roots can easily spread to access water and nutrients and your garden will thrive. Make sure your soil is aerated to at least 250 mm deep. Depending on your garden or lawn area, manual forking may be sufficient to decompact or aerate your soil. Large areas may require specific machinery. Grass clippings and leaf mould – ensure they are thoroughly mixed into the soil. do and don’t TIPS • Do dig the decomposed organic matter through your topsoil before planting. • Do apply organic matter regularly, as it breaks down, especially in sandy soil. You need to be persistent – it may take several years to improve a poorly structured soil. • Don’t dig clay or clay loam soil when it is wet – you’ll only add to the compaction. improving your soil The key to saving water is to ensure you have enough topsoil, at least 250 mm, with a good structure (regularly aerated) and texture (ideally sandy loam or loam). You can improve poorly structured soil by using both physical means such as digging, aerating or ripping and also by incorporating decomposed organic matter. will gypsum help? Adding gypsum (calcium sulphate) is often recommended to improve poorly structured clay soil, but it doesn’t work on all clay soil—only on what is called ‘sodic’ clay soil. In a typical Canberra clay soil, physical disturbance using digging, aeration or ripping breaks soil crusts and allows water to penetrate to depth. Adding organic materials such as humus to the soil binds the particles together into crumbs, opening the structure, allowing water to infiltrate and to drain more freely. Decomposed organic matter also adds nutrients to the soil. It is best to use organic matter that has been composted to ensure it contains no toxins or diseases. Avoid uncomposted woody materials. Before you spend your money on gypsum, seek expert advice or try this quick test. Take a 5mm clump of soil and place it in a jar of rainwater or deionised water. Don’t disturb the jar for 24 hours. If the aggregate remains unchanged or falls apart into smaller aggregates that remain where they are, gypsum won’t help your soil. 2 Water repellent soils If your soil is hydrophobic, water will not enter the soil or be available for your plants. The water will puddle on the surface and evaporate, drop straight through leaving the soil dry, or you’ll see the water stay in beads and then run off without sinking in. Apply a wetting agent or surfactant to the soil to reduce the surface tension of the water and help it penetrate the soil. If the clump has dispersed after 24 hours, producing a general cloudiness in the water, gypsum will improve the soil. In this case, apply 1-2 kg per square metre and dig or water it in. Soil depth Soil depth is the distance you can easily dig down before you hit an impenetrable layer such as hard clay or rock. The deeper the soil (and the better its texture and structure), the more water it can hold, and the less you need to water. Soil wetters are also useful for potted plants when the potting mix has become hydrophobic and you see the water you apply pour down the inside of the pot and out the drainage holes. The top layer is usually composed of organic matter. While some plants can be very deeprooted, the majority of garden plants have fine feeder roots about 300 mm deep. So a water efficient garden should have good quality soil to at least 250 mm depth. Soil wetters come in granular form that you sprinkle on the surface of the soil and lightly dig through. You can also buy liquid wetting agents. Hose-on liquid applicators are good for turf areas where water is running off the grass rather than penetrating the soil. If you apply a liquid wetting agent using a watering can, first put the water in, then add the recommended amount of wetting agent and stir well. If you put the liquid wetting agent in first, it will produce suds that froth everywhere. Liquid soil wetters are detergent based, so they will degrade and need to be applied regularly. In Canberra this can be done using several methods, with varying degrees of effort depending on the condition of your soil. First check your soil and then consider using some of the methods detailed in the section on improving your soil. When making new garden beds, combine the new soil with some subsoil of a different texture to avoid placing topsoil over a compacted layer of clay or rock. This will prevent roots hitting a water well, sitting on the impenetrable layer and becoming waterlogged. Water crystals Many people confuse soil wetters with water crystals. Water crystals are synthetic plastic materials that swell into a jelly-like substance when they absorb water. Another method is to mound imported soil on top of the original soil to create free draining and nutrient rich garden beds. Use a good quality garden mix appropriate to your plant choice. Be sure to aerate and disturb the soil that will be beneath your mounds to ensure that waterlogging does not occur. Make your mounds between 200 and 300 mm deep. Only use hydrated crystals as a slurry in the planting hole around the roots of new plantings. Do not sprinkle dry crystals on the surface of soil or potting mix. If you do, they will swell up and absorb water that they remove from the soil. It is also best to avoid using water crystals when planting native species. When cultivating the soil, loosen any compacted subsoil, but do not bring clay subsoil to the surface by digging too deeply. Soil should be watered deeply and infrequently. Frequent light watering encourages more root growth nearer the soil surface that dries out quicker. The aim of deep watering is to fill the 250 mm ‘reservoir’, making water available at the root zone and encouraging roots to go deeper. High water use plants such as vegetables, ferns and shallow rooted annuals need more frequent watering. MORE INFORMATION Website: www.actsmart.act.gov.au Ph: 13 22 81 Email: [email protected] Printed on 100% recycled paper Jan 2012 WRG-G 11/1716 3 WaterRight Gardens Webtool Canberra Plant Selector Not sure how much water you need to keep your garden looking good? Need help to choose plants suitable for your garden? Find out how plants, your soil, wind, shade and the seasons affect your garden and lawn watering needs. The Canberra Plant Selector enables you to look up information on a range of plants found in Canberra gardens. Enter your garden details into the WaterRight Gardens Webtool to produce watering schedules and other helpful tips. Knowing the growth habit, sun, shade and frost tolerances and the water requirements of plants can help you choose plants suited to your garden, and save water. You can find the WaterRight Gardens Webtool at www.actsmart.act.gov.au or call Canberra Connect 13 22 81 for more information. You can find the Canberra Plant Selector at www.actsmart.act.gov.au or call Canberra Connect 13 22 81 for more information. Sources of water for your garden Rainwater, greywater and bore water can be great sources of water for garden watering, particularly when used with efficient watering methods. RAINWATER TANKS A simple way to use rainwater is to connect a tank to the closest downpipe and use a bucket, watering can, or a gravity-fed irrigation system to water the garden. This avoids the need for a pump. If you would like to achieve more water savings through the use of your tank, you can also have it plumbed into your home for use in clothes washing or toilet flushing. A pump is usually necessary to boost pressure and flow if you are plumbing your tank water into your toilet or washing machine, or using it in an irrigation system that requires pressure to operate. Tank Size The size of tank best suited to your needs depends on a number of factors, including: • the area of roof available to capture the rain; • how you plan to use the rainwater; • the available space to install a tank; and • the number of people in your house (if you plan to use the rainwater inside as well as in your garden). Approvals and regulations The Environment and Sustainable Development Directorate (ESDD) can advise on any development, building or plumbing approvals required, and any plumbing regulations that must be met, for the installation of your tank. More information on rainwater tanks The ACT Government’s Rainwater tanks – Guidelines for residential properties in Canberra (available from www.actsmart.act.gov.au) provides information about installation requirements, issues to consider, regulations and approvals, as well as tables and charts to assist you to choose the right size tank for your household. You can also estimate your water savings per year using the residential waterways calculator at www.environment.act.gov.au GREYWATER Greywater is wastewater generated from hand basins, showers, baths and spa baths, washing machines, laundry tubs, kitchen sinks and dishwashers. This fact sheet does not address blackwater use, which is wastewater generated from toilets, urinals and bidets. Source of greywater suitable for your garden Generally washing machine rinse-cycle water and basin, bath and shower water are the most suitable sources of greywater for garden watering. If you use low-salt, phosphorus free detergents you may not need to restrict the use of washing machine water to the rinse cycle only, and could use all the laundry water with care. However, laundry water from soiled nappies or wash water from domestic animals should not be used. Greywater from kitchen sinks and dishwashers contain fats, oil and food particles. Often it is chemically polluted with alkaline detergents and cleaning agents, which over time may damage the soil and your plants. Kitchen water from these sources is not suitable for reuse on gardens. Storage and treatment of greywater Untreated greywater must not be stored for more than 24 hours, as it may create a health risk due to the growth of microorganisms. Storage of greywater can also cause offensive odours. • • • Greywater treatment systems are designed to remove microorganisms and pollutants from greywater, so it can be stored for longer periods. Before installing a treatment system, you should consider the costs involved, as well as your responsibility to ensure the system is maintained so it does not create a public health or environmental risk. Greywater treatment systems will require regular maintenance , such as cleaning or replacing of filters, and desludging of the holding tanks. Often a professional is required to ensure the system is operating efficiency. • • • • • Moving greywater into the garden The simplest systems involved diverting greywater from the washing machine and/or bathroom directly to the garden or lawn. This can be achieved by: • Using a bucket or siphon to transfer water; • Connecting the washing machine discharge hose to a diversion hose leading to the garden. A washing machine pump is designed to operate with minimal resistance. To protect the pump from damage, use a large diameter hose and only divert to areas lower than the height of the washing machine; or • Fitting the laundry tub waste pipe with an approved hand-operated diversion valve. You can then easily switch the plumbing diversion device to divert greywater, by gravity, from the laundry tub through a hose to the garden. This valve must carry a Watermark approval and can only be installed by a licensed plumber. • • Don’t store untreated greywater for more than 24 hours. Don’t use domestic garden hose that may be used for other purposes to distribute greywater. Only apply enough greywater to the soil to absorb, and ensure your greywater does not pool or pond, or leave your property. Avoid greywater use when the soil is wet or rain is imminent. Regularly move the distribution point for greywater to different parts of your garden. Water greywater-irrigated areas periodically with tap or rainwater to reduce salt build up. Stop using greywater if odours are generated and plants do not appear to be healthy. Avoid spraying or sprinkling greywater. The best irrigation systems for greywater are piped under the ground, although some people also use drip irrigation or put piping under mulch. Don’t use greywater on food plants that are eaten raw. Don’t use greywater where children or pets (especially dogs) are likely to play. More information on greywater For more detailed information on greywater reuse see the ACT Government’s Greywater Use – Guidelines for residential properties in Canberra, available from www.actsmart.act.gov.au BORES In the ACT, new bores are no longer allowed on urban residential properties. Where there is an existing bore it can provide a valuable alternative to portable water. The reliability of a bore can vary with time and is influenced by both climate and extraction rates. The cost of operation and maintenance depends on how deep the water lies below the surface. The quality of bore water can vary significantly and often has a high concentration of salts and dissolved minerals such as iron and calcium. These can have a detrimental effect on soil structure and plant growth, and may block tap and irrigation fittings. Tips for safe use of untreated greywater • Only use greywater from washing machines (preferably the final rinse water), baths and showers. • Choose biodegradable cleaning products that contain no phosphorus and are low in salts. Concentrates and liquid detergents generally contain less salt. The effects of bore water are increased where evaporation is high, since this further concentrates the salts in the soil. It is recommended that bore 2 water is tested prior to use and periodically over the life of a bore to ensure it is a suitable quality for its intended use. MORE INFORMATION Website: www.actsmart.act.gov.au Ph: 13 22 81 Email: [email protected] Depending on the quality of your bore water, your tank bore and pump may require regular maintenance. Also, bore water that is high in dissolved minerals and salts may damage plant foliage, so always water the plant root zone. In the ACT, a Water Access Entitlement must be held before a licence to take water can be issued. A licence to take water is required for every bore. Printed on 100% recycled paper Jan 2012 WRG-H 11/1716 3 WaterRight Gardens Webtool Canberra Plant Selector Not sure how much water you need to keep your garden looking good? Need help to choose plants suitable for your garden? Find out how plants, your soil, wind, shade and the seasons affect your garden and lawn watering needs. The Canberra Plant Selector enables you to look up information on a range of plants found in Canberra gardens. Enter your garden details into the WaterRight Gardens Webtool to produce watering schedules and other helpful tips. Knowing the growth habit, sun, shade and frost tolerances and the water requirements of plants can help you choose plants suited to your garden, and save water. You can find the WaterRight Gardens Webtool at www.actsmart.act.gov.au or call Canberra Connect 13 22 81 for more information. You can find the Canberra Plant Selector at www.actsmart.act.gov.au or call Canberra Connect 13 22 81 for more information.