By Todd Layt
Australians are very creative at finding ways to have a green garden, even in times of water restrictions. Here are some ideas to help you create green spaces that can survive most water restrictions, including useful tips on grey water systems, water tanks, no irrigation gardening plants, best mulch types, best turf varieties and more.
Water tanks and grey water systems
We can't wait for the government to provide us with water for gardens, so the best thing to do is to organise your own supply. You can do this with water tanks, or even better, grey water systems. Water tanks are easy to find and there is plenty of information available. The main thing to think about is that small tanks don’t offer a good long term solution, as water in smaller tanks can be quickly used up in times of drought. Put in larger tanks to last longer; there are now some good sized tanks that come in a variety of shapes and sizes. There are some that are thin and narrow, some that fit under the house and stylish tanks that become part of the landscape. Any tank less than 4,000 litres is a bit small to provide a good back up water supply. If you're limited for space, install a few smaller tanks in sequence to make up the volume needed.
The information that's available on grey water systems is a bit more confusing, so I've gathered information on 3 good systems that seem to work and are easy to organise to be installed. Whenever possible, forget the small installations that just divert water from washing machines, as the amount of water is so negligible. Only about 50% of existing homes can have storage grey water systems installed, so if feasible, it is better to do it at the time of building.
Basically, houses on stumps, or a reasonable amount of two storey houses on slabs, can have their waste water split into grey water (from showers, taps, and laundry other than kitchen waste or toilets), and black water (from kitchen waste and toilets). The black water is sent down the sewerage, and the grey water is recycled and stored with these systems. I'd suggest only using systems that produce class A or class A+ water, so that storage is allowed.
Water storage is essential if a long term solution to water restriction is to be found. Two good grey water recycling systems that use biological processes are the Nubian (www.nubian.com.au) and AquaReviva sytems (www.newwater.com.au). Both of them can clean and store up to 1,500 litres of water per day, although most families only make about 500 litres of grey water in a day. Systems like these cost around $10,000 or more which is a lot of money, but this could be a gardeners ticket to freedom from water restrictions.
Older single story houses on concrete slabs can rarely be split into the 2 water categories needed for grey water recycling. This is where the recent invention of the Econova (www.econova.com.au) comes in. This system recycles both black and grey water into A+ class water good enough to drink. However, as usual, our governments are moving slowly on this issue. In non-sewered areas, this system is allowed for black water recycling in Queensland and NSW, but nowhere has it been approved for use in sewered areas.
So our governments say "you cannot water your gardens with our water, and only about half of homes can, in practical terms, recycle their waste water". Typical bureaucracy! I know this technology has only been available since November 2006, but time is of the essence here. It is time governments got a move on. Apparently Victoria and South Australia are looking at it at the moment.
Thinking about the landscape
Now that your landscape has guaranteed access to water through a non-government water supply, you can consider your landscape. Firstly, for a choice between using a lawn or garden. The truth is that many native gardens use about the same water as lawns. The University of Western Sydney published a study which showed primarily native gardens used 4.7 kL of water/100m2/month, whilst warm season turf such as Kikuyu, Buffalo grass and Couch used 4.3kL of water / 100m2 / month. Primarily, exotic gardens used 8.7 kL of water/100m2/month; approximately twice as much as lawns and native gardens.
Lawns such as Palmetto® Buffalo or Empire™ Turf can be extremely drought tolerant compared to water hungry lawns such as Fescue and Rye Grass. Native Dianellas like Little Rev™, Little Jess™, Tasred® and Cassa Blue®, and Lomandras such as Tanika® and Nyalla® are so tough, that in the eastern states they thrive on no irrigation at all. If you want more water hungry plants, keep them to one small area of the garden so as to not waste a lot of water.
Mulch is another great water saving device, but beware, some mulches will actually reduce the amount of water available for plants. Basically, good chunky mulches, with no or very small amounts of fine particles help retain water and work well. Mulch with a high proportion of fine grade material have in research sponsored by Yates, shown that they can actually repel water, making a garden dryer. Shade around a garden can reduce evaporation. This can be either from a few well placed trees, or a garden that is densely planted with few gaps.
The vegetation covered areas will be cooler and allow for much slower drying out of the soil, especially if the right plants are used. Having fewer gravel or concrete areas and more greenery will also keep landscaped areas cooler, again reducing garden dry out.
Tips for the summer months
• For both lawns and gardens, make sure at least every spring a wetting agent is applied. Dry patch in plants and turf, is in my opinion, the greatest reason why drought tough plants and turf fail in patches.
• Aerate lawns in spring to reduce compaction.
• Mow lawns a little longer in the hot months.
• When watering a lawn or a native type garden, water infrequently, but heavily. For example; in hot summer months, if it has not rained for a while, save the water in your tank for one or two good waters rather than lots of small waters. (In sandy soil areas such as Perth, more frequent watering maybe necessary).
• Avoid watering in the heat of the day, so as to maximize the water getting into the ground.
• If you need to hand water, split the garden and lawn into 4 sections. Water each section more heavily and less frequently.
Remember: secure your water supply, choose plants and turf that need less water and use smart water wise maintenance techniques.