Plants have a much better chance of surviving drought and scorching heat if they are set up to withstand these stresses in the first place. “You can prepare for dry spells well ahead of time by drought-proofing the soil itself with generous additions of water-retaining compost; homemade is best!” says Robert Guyton of the South Coast Environment Society (sces.org.nz).
Bare soil quickly loses moisture, so mulch is your first line of defence. A five centimetre layer of chipped bark, pea straw, coir or untreated wood chips will greatly improve moisture retention on hot days. Mulch also helps to suppresses weeds and supplies nutrients to the soil as it breaks down. But don’t over apply – too much will prevent water getting in and may restrict air flow to the soil and suffocate your plants.
Before mulching, add compost to your soil to help it absorb and hold onto moisture, or try a soil wetter such as Debco SaturAid to improve water retention. Make sure you water before applying mulch and keep it away from the stems and trunks of your plants to prevent them rotting.
It’s important to save water, so be mindful of your usage and keep abreast of water restrictions in your area.
Water in the early morning or early evening to minimise evaporation. A good soak rather than a light sprinkle is the best option. “In hot, dry weather, I give my garden a deep watering two or three times a week,” says garden writer Rachel Clare. “By watering less frequently but deeply, it encourages plants to send roots deeper into the soil where it’s cool.”
To save time and water most efficiently, invest in an irrigation system. Drip irrigation is extremely effective at delivering water to the roots of plants in the right amounts. It can also be linked to an automatic or smart timer, and with a rain sensor attached, it will only water when needed. Drip irrigation provides water directly to the base of plants, while sprinklers can lose 30-50 per cent of the water to evaporation in high temperatures, and also spray beyond where it’s needed.
Plants originating from low rainfall areas, such as parts of South Africa and the Mediterranean, are better suited to summer survival. Look for rosemary, thyme, lavender, rockrose, agapanthus, proteas, leucadendron, Dietes grandiflora (fairy iris), plumbago, gazanias and African daisies. Many of our native plants are dry-tolerant too, such as corokia, coprosma, Griselinia littoralis (Kapuka), muehlenbeckia, Carex buchananii (Buchanan’s sedge) and Brachyglottis greyi (daisy bush). Other drought-tolerant plants include salvias, grevilleas, Gaura lindheimeri (Lindheimer's beeblossom), lamb’s ear and silverbush.
Greywater is the wastewater from showers, baths, basins and laundries, which can be redirected to the garden. Be aware that setting up a collection and use system for greywater requires a building consent and it must be installed by a certified drainlayer. The greywater is released under the soil rather than on top of it and should not be discharged into food gardens. For a low cost approach, collect greywater in a bucket from an area where there is no contamination risk, such as your shower. Tip the water from the bucket onto your non-edible garden or lawn within 24 hours. For added nutrients, incorporate Yates greywater fertiliser, which also contains a biocide to help reduce any bacteria.
Smarter Homes (smarterhomes.org.nz) suggests talking to plant specialists about which particular plants thrive in greywater, advising that it tends to be alkaline.
Check out our step-by-step guide on planning an irrigation system to see how easy it is to keep your garden hydrated.
Some products are not available at all Bunnings stores, but may be ordered.
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