Water Efficient Gardens Manual - New South Wales, Australia

1. Updated 22 November 2004
WATER EFFICIENT GARDENS
WATER EFFICIENT GARDENS ........................................... 1
YOUR GUIDE TO SAVING WATER IN THE GARDEN .................................. 2
GARDEN DESIGN ..................................................................................... 3
Zoning ..................................................................................................................... 3
PLANT SELECTION.................................................................................. 4
SOIL IMPROVEMENT............................................................................... 4
Aerate – let your soil breath.................................................................. 5
Mulch - the more the better .............................................................................. 5
Products to improve watering efficiency ....................................................... 5
GARDEN WATERING............................................................................... 6
Ways to water ..................................................................................................... 6
When and how much - the Irrigometer .......................................................... 7
Potty about pots .................................................................................................. 7
Wastewater reuse on your garden ................................................................. 7
LAWNS ......................................................................................................... 8
RAINWATER TANKS ............................................................................... 9
OTHER OUTDOOR ACTIVITIES ........................................................... 9
FOR FURTHER INFORMATION… ........................................................ 9
National Water Conservation Labelling and Rating Scheme ................. 10
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2. Updated 22 November 2004
YOUR GUIDE TO SAVING WATER IN THE GARDEN
In the Australian landscape water is a precious resource, therefore, conserving water is one of
the best ways to protect our unique and beautiful environment.
In the Rous Water supply area water use on gardens and activities conducted outside the
house accounts for over 30% of all household usage.
This booklet provides practical information and ideas to help you save water in your garden.
Many of the tips are designed to encourage hardier plants and landscapes. This means
reduced maintenance time and costs for you, while keeping your garden looking great through
the good times and the bad!
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3. Updated 22 November 2004
GARDEN DESIGN
A water efficient garden starts with planning and good
design. This is easier when planting a new garden.
However, if you have an established garden it does not
mean that you have to pull it all up and start again – it’s
simply a more gradual process that involves working
with what you have. Target areas of your garden for
improvement and review your current maintenance and
watering activities.
Spend some time in your garden to understand where the
sun rises and sets, the direction of prevailing winds
(summer and winter), where there is shade from existing
features such as trees and buildings, and the drainage
direction.
Also consider how you use your garden, and if these activities will change seasonally. This
includes outdoor activities, such as gardening, play areas and socialising, as well as practical
spaces for BBQ and entertaining areas, a washing line, waste storage and cars. Also think
about traffic patterns and the amount of privacy you want.
When drawing up a plan, for each component take water into consideration (e.g. direct
rainwater run-off from downpipes towards high water-use areas). The two most important
design elements for a water efficient gardening are grouping (or ‘zoning’) plants of like water
needs together and eliminating, or reducing, your lawn area to a minimum.
New plants tend to require large and frequent watering to get them established. To give your
plants a better chance at life undertake any major plantings when the conditions are good.
Zoning
Select plants that suit your garden and soil conditions. Grouping plants with similar water
needs together into zones makes watering easier and ensures that plants only get the water
they need.
High water use: Lawns, vegetables, fruit trees, exotic shrubs like azaleas and camellias,
flowering herbaceous annuals and many bulbs.
Medium water use: Hardy vegetables like pumpkins and potatoes, hardy fruit trees and vines
like nut trees and grapes, many herbs, some exotic shrubs, most grey or hairy leafed plants,
roses and daisies.
Low water use: Most Australian natives including banksias, grevilleas and eucalypts, some
exotics from South Africa, California and the Mediterranean, succulents and cacti, olive trees
and some exotic ornamentals, such as bougainvillea.
Plant trees to create natural shade and windbreaks to reduce evaporation. High water use
plants are best located where they can be sheltered from drying winds and strong sunlight.
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PLANT SELECTION
Local indigenous plants have adapted to local conditions, while many other Australian native
plants have evolved to cope with limited water. Incorporating native plants into the garden
also provides habitat and food for birds and insects, which in turn aid in pest control and
pollination.
Before selecting plants consider the soil type of the site, the limiting factors (e.g. frost,
exposure to salt) and the function required (e.g. bush foods, shade). The following are some
suggested plants for the NSW Far North Coast area. For further suggestions ask at your local
nursery or plant retailer.
Coastal: sandy soils, frost free saline conditions
Species name Common name Growth habit
Carprobrotus glauescens Pig Face Low < 1m
Lomandra longifolia Coast Mat-Rush Low < 1m
Hibbertia scandens Guinea Flower Low < 1m
Syzgium oleosum Blue Lilly Pilly Medium 2 - 4m
Acacia sophorae Coast Wattle Medium 2 - 4m
Casuarina glauca Swamp Oak High > 5m
Inland: frost-prone, variable soils
Species name Common name Growth habit
Omalanthus populifolius Bleeding Hearts Medium 2 - 4m
Elaeocarpus reticulatus Blue Berry Ash Medium 2 - 4m
Backhousia citriodora Lemon Myrtle Medium 2 - 4m
Banksia integrifolia Coast Banksia High > 5m
Polyscias elegans Celerywood High > 5m
Maintaining trees and shrubs by regular pruning reduces the amount of water required. This
also encourages flowering and maintains plant appearance.
SOIL IMPROVEMENT
One of the most important elements of a water efficient garden is the quality of the soil.
There are three main soil types - sandy, loam and clay – each with a different water holding
capacity.
• Loam soils are high in organic materials are able to hold the most moisture - this is the soil
condition to strive for.
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• Sandy and clay soils can be improved by incorporating well-decomposed organic matter
such as compost, manure and mulch to a depth of 15 to 25 cm.
• Clay soils can be improved by adding gypsum (0.5 – 1.0 kg per square metre) or by
growing hardy, deep-rooted plants.
Aerate – let your soil breath
Aerating the soil in your garden allows for better absorption of water. This is particularly
effective on lawn areas where compaction may be a problem. There is a range of ways to
aerate soil, depending on the size of your garden. For smaller areas you can purchase strap-on
soles with spikes and simply walk around your garden, or if you are feeling energetic use a
pitchfork. For larger areas you can hire a lawn aerator (a roller with spikes).
Mulch - the more the better
Mulch, mulch and more mulch. It can’t be said enough that mulch is fantastic for your
garden, and can increases water retention by the soil by about 80%. Organic mulch provides
materials and nutrients essential to plant health, reduces the need for weeding and it looks
great!
For best results apply mulch to a depth of least 15cm thick (avoiding the area immediately
around plant stems and tree trunks) and re-apply at least once a year, or as it breaks down.
Mulch can be in the form of leaves and grass clippings, manure, compost, rocks and gravel,
straw and other crop residues, worm casts, newspapers, bark and woodchips.
Products to improve watering efficiency
Use a soil wetting solution or granules to increase soil “wettability” and water absorption, and
decrease water run-off. Wetting solutions are effective on lawns, garden beds, as well potted
and hanging plants. Use according to instructions on the package.
Soil moisture crystals are small crystals that swell to 100’s of
times their size in water. They act to retain water in the soil,
so that the water is available to plant roots for longer.
Moisture crystals are great for potted and hanging plants. For
established pots remove a small amount of soil from around
plants (at least 5 cm deep), sprinkle crystals and replace soil.
Alternatively, mix crystals through potting mix when re-
potting.
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6. Updated 22 November 2004
GARDEN WATERING
Water in the early morning or in the evening, as this allows water to penetrate before it
evaporates. Watering early in the morning allows the sun to activate the water (by producing
water vapour and stimulating micro-organism activity) to generate the food that plants will
draw on during the day.
Water your garden longer and less frequently. Letting the soil dry out between watering
encourages deep root systems and helps plants to be less dependent on regular watering.
Water the roots, not the leaves, as water on the leaves evaporates easily and can lead to
scorching.
Water the highest part of the garden first so that any run-off soaks into the lower dry areas.
Avoid watering in windy conditions as water is lost by evaporation and dispersion.
Controlling weeds reduces competition for water with your plants. Fertilise plants with
organic liquid fertiliser as dry fertilisers take water from the soil and can raise salt levels.
Ways to water
There are a number of methods for watering your garden, and combined with your watering
schedule your irrigation system is one of the greatest influences on water use.
For hand-held hoses use a “trigger” hose nozzle. These attachments
ensure better control and avoid wasted water when moving around your
garden.
Use a tap timer when using soaker hoses and
sprinklers. Alternatively, set the timer on your oven
as a reminder to move, or turn off, the sprinkler. A
forgotten sprinkler can waste up to 1000 litres of water an hour.
Fixed irrigation systems are made up of a series of PVC piping, risers and
sprinkler heads, generally installed in the ground. The sprinkler heads come in a variety of
patterns, which use varying amounts of water and are suited to different types of plants.
Fixed irrigation systems that are poorly designed and maintained use more water than hand-
held hoses. When installing a fixed system, planning is essential to ensure optimal operation
and the most efficient use of water. Consult a landscaper or your local garden centre on the
system most appropriate for you and your garden. Many garden suppliers on the Internet also
provide detailed information.
Drippers Most water efficient as it delivers water to the
roots of individual plants and minimises evaporation and wind drift.
Good for watering individual plants, such as trees, vines and shrubs.
Subterranean drippers are great for lawns.
Misters Most suitable for hanging baskets, delicate ferns,
shade houses and plants that require high humidity. Fine droplets
are lost in windy conditions.
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Microsprays Available in a variety of spray shapes (e.g. full
circle, strip). Good for plants in garden beds. Fine droplets are lost
in windy conditions.
Sprinklers Pop-up, impact. Apply water over a larger area
and are less effected by wind.
Automatic fixed systems set to turn on regardless of weather
conditions and soil moisture content will waste water. Systems not
adjusted to seasonal needs may deliver water too fast, resulting in
run-off, or supply more water than plants require.
Soil moisture sensors trigger cut-off switches on automatic systems
when it rains, and adjust watering duration according to soil moisture
levels.
When and how much - the Irrigometer
The irrigometer or “catch cup” allows you to measure the correct amount of water for gardens
in the Northern Rivers area.
In the dry season most soils require about 25 mm of water to reach 25 to 30 mm depth in the
soil. Depending on the type of sprinkler this means 1 hr per week on clay soils and two
waterings of half an hour twice a week (12 mm) for sandy soils (more common on the
coast).
To check the amount of water that your sprinkler is delivering, and therefore the amount of
time you need to leave it on, simply place the catch cup in the garden, turn on the sprinkler,
and note the time it takes to reach the desired levels marked.
Potty about pots
Most gardens have potted or hanging plants as displays or decorative features. These can be
high maintenance as their small size means that they require regular watering. Water pot
plants by soaking them in water for a few seconds until the bubbles disappear. Drip irrigation
is best if you have, or are selecting, a fixed irrigation system.
Seal porous pots, such as terracotta, before planting or use ceramic or plastic pots. There are
also several products available to increase the moisture holding capacity of the soil (see
above).
Simply moving potted plants into the shade during hot weather will reduce water loss through
evaporation.
Wastewater reuse on your garden
Household wastewater from the bath, shower, hand basin, laundry and kitchen sink is known
as greywater.
For health and environmental risks kitchen greywater can only be reused following treatment
in an approved greywater treatment system.
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Wastewater from the bath, shower, hand basin and laundry can be reused for watering the
garden by way of sub-soil irrigation or sub-surface irrigation using a greywater diversion
device.
This device enables you to divert one or more of the above wastewater streams from the
drainage system under the house. Often there is a course filtering system prior to greywater
being redirected for sub-soil irrigation (i.e. a trench at a depth greater than 300 mm below
ground) or sub-surface irrigation (i.e. trickle or drip irrigation at a depth between 100mm and
300mm below ground).
Approval is required from your local council to install a greywater diversion device. For
further information refer to the following documents and your local Council.
NSW Health (2000) Greywater Reuse in Sewered Single Domestic Premises.
http://www.dlg.nsw.gov.au/dlg/dlghome/documents/Information/Greywater%20ReUse.pdf
NSW Health (2000) Domestic Greywater Treatment Systems Accreditation Guidelines.
http://www.health.nsw.gov.au/public-health/ehb/general/wastewater/greywater.pdf
LAWNS
Lawns are thirsty, using up to 90% of water used
on gardens. They also take the greatest amount of
time and money to maintain, as they need mowing,
weeding, edging and fertilising.
The easiest way to save water is to reduce
lawn area by creating garden beds or replacing with
porous paving, pebbles or drought-tolerant
ground covers such as prostrate grevilleas,
snake vine (Hibbertia scandens), or
myoporum. Seek advice at your local plant
nursery.
Different grass types have different watering
needs. Select a turf that needs less water and is
suited to the region, such as mondo grass, buffalo and compression grass. There are also
herbs, such as Dichondra that are suitable for low–traffic areas. Turfs to avoid include couch,
kikuyu and millets. Ask your local plant nursery for the most suitable low water species for
your climate and soil type.
Soil preparation prior to laying turf is also important in encouraging a drought hardy lawn.
Laying turf on a layer of sand-based topsoil will encourage deep root systems.
Avoid cutting your grass so frequently as taller grass holds more water. Set your mower to cut
4 cm or higher. This encourages a deeper root system and the longer grass blades shade the
soil, reducing evaporation.
Water the lawn only when it is showing signs of stress. Long, slow soakings that allow water
to penetrate to a depth of about 15 cm will encourage a deeper, hardier root system.
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RAINWATER TANKS
Rainwater tanks and other rainwater harvesting technologies, such as water-storing guttering,
may provide households with an additional source of water. Rainwater tanks can be
integrated as part of garden irrigation systems, and may have the potential to be used for toilet
flushing (in this instances a backflow device is essential to prevent rainwater entering the
mains water supply). To make the most of your investment in a rainwater tank, contact your
tank supplier for information on the most suitable size for your roof area and water
requirements, local rainfall conditions and possible plumbing arrangements.
Check if your local Council requires a development application to install a rainwater tank.
OTHER OUTDOOR ACTIVITIES
Water is used outdoors for activities other than gardening and these also provide opportunities
for savings.
Wash your car, or boat at a car wash that recycles water
and detergents. If washing the car (or dog!) at home, use
a bucket and do it on the lawn to prevent water and
detergent flowing down the drain. Choose a different
place on the lawn each time.
Swimming pool covers significantly reduce evaporative
losses and can save between 11,000 and 30,000 litres of
water a year. Lower the pool level to reduce loss from
splashing and overflow when pool is being used.
Use a broom instead of a hose to clean paths and the
outside of buildings.
FOR FURTHER INFORMATION…
There is a broad range of books and Internet sites on saving water in the house and garden.
Your local supplier of garden products is also a great source of information on water efficient
gardening in your area. Some examples are listed below, or do a search on the web – you’ll be
surprised with what you come up with.
Archer, J., Hodges, J. and LeHunt B. (1993). The Water Efficient Garden. Random House,
Australia.
Garden Guide. Angus & Robertson, Australia. Yates (1998 ed. only).
van Dok, W. (2002) The Water-efficient Garden: A Guide to Sustainable Landscaping in
Australia. Water Efficient Landscapes, Australia.
Waterwise Western Australia. Waterwise brochure series edited by John Colwill.
http://www.greenhouse.gov.au/yourhome/index.htm
http://savewater.com.au
http://sydneywater.com.au
http://www.abc.net.au/gardening/
http://www.austplants-nsw.org.au/studgrp.htm
http://www.au.gardenweb.com/forums/oznative/
http://www.toro.com.au/index.cfm/content/display/40
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National Water Conservation Labelling and Rating Scheme
This scheme provides consumers with information on the relative water efficiency of products
and is administered by the Water Services Association of Australia (WSAA).
The scheme covers washing machines, dishwashers, showerheads, toilet suites, taps and
commercial urinals. Labels are displayed on merchandise in the form of a 'rating label'.
For further information about the labelling scheme, see the WSAA web site at
http://ratings.wsaa.asn.au
For more information about Australian Standards, see their web site on
http://www.standards.com.au
Contact Rous Water on 6621 8055 for information on the latest programs aimed at
reducing water use.
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