Drought-proofing your garden
in Greener Homes on 4 October 2009
Gardens can thrive despite the drought.
It’s never too late to ready your garden for summer, says Anna Thirkell-Johnston, from Bulleen Art and Garden nursery, “but you’ve got to get onto it as soon as you can.” On October 15, she’s hosting a seminar on drought-proofing your backyard.
A number of tactics have begun to seep into common knowledge. Water tanks offer some independence from the mains: the larger the capacity, the better. Recycling greywater also boosts your supply, but it requires careful research and implementation.
When it comes to watering, it’s best to use a drip irrigation system and cover your garden beds with about ten centimetres of mulch – both steps will reduce evaporation and wastage.
But above all, Ms Thirkell-Johnston says, it’s important that people understand that soil is their biggest water storage device. “Organic matter is like a sponge in the soil,” she says. “Soils that have high organic matter hold a heck of a lot more water than those that don’t.”
She recommends gardeners build up their soil by adding compost and mulch to create humus – that’s the rich, dark and fertile soil that absorbs extra water. Moisture retention products such as crystals and wetting agents can be effective, she adds, but only if used correctly. Most people tend to use them too much.
On plant selection, Ms Thirkell-Johnston says there’s no substitute for study – search plant encyclopaedias or Google to find out what conditions suit the plant you’re considering.
Cam Wilson from Forest Edge Permaculture says a garden can be water-smart and productive. “A well-mulched backyard garden uses about one-fifth the water that a market gardener needs to grow the same amount of food.”
He recommends digging basins and trenches (about thirty centimetres deep) on the upper side of trees and shrubs. “If it’s been hot and dry, the soil doesn’t receive water very well. When you have a downpour, it rushes off the surface of your property,” he says. “The basins will intercept the runoff and hold the water, giving it time to infiltrate the soil.”
To avoid your yard “looking like a motocross track”, fill the trenches with mulch. “A tree-lopper can often drop off quite a large load of chips for $80 or $100.”
Drought-solutions can be attractive features. For a recent project, Mr Wilson created a dry creek bed, feeding from a shed downpipe. “It’s got disguised infiltration basins on the way down to water fruit trees, and they overflow into a frog-pond.”
He says it’s also crucial to shelter your garden beds from the hot western sun and from dry north winds. Try growing a grape on a trellis to the west – its deciduous leaves will offer summer shade.
To the north, he suggests planting a windbreak. “It reduces evaporation by a huge amount. I often recommend planting an Acacia hedge, which can be chopped back hard after summer to allow winter light. The prunings make an excellent mulch under fruit trees.”