How to help your garden survive a heatwave
Don’t let a bout of hot weather ruin your garden. There are easy ways to keep your garden thriving even through a heatwave. The key messages are to make sure the garden (especially new and potted plants) is well watered ahead of and during a heatwave, shade vulnerable plants, and use mulch to keep the soil cool and moist.
Here are our top tips to help you keep your cool when temperatures rise, and the garden starts to wilt.
Tip 1: Prevention is better than a cure!
Be proactive and apply a protective, spray-on film now, such as Yates Waterwise DroughtShield, to minimise transpiration and protect against stress and sunburn. This product is available at your local Flower Power Garden Centre and comes in a ready-to-use spray pack so it's easy to apply. It is particularly useful to protect vulnerable plants such as new plantings and fine-leafed trees such as maples and magnolias that are prone to burning. It can also help protect frost-tender plants against frost in winter.
Tip 2: Provide coverage.
Offer shade on unseasonably warm days by erecting temporary shadecloth covers, particularly for new plantings and heat-sensitive plants such as hydrangeas. It's also important to avoid damage from reflected heat that radiates from paving, masonry walls or metal fences exposed to sun, and which can cause nearby plants to burn, even if the plant is in the shade. Use temporary covers such as laying cardboard over a hot path or placing shadecloth or hessian between a hot vertical surface and a plant.
Tip 3: Mulch your garden beds.
Keep gardens well mulched to assist with water retention in the soil and to prevent them drying out. Mulch also keeps soil cool. Bare earth exposed to hot sun can get so hot that the roots in the soil can burn. A 5-7cm layer of organic mulch such as sugar cane, lucerne or pine bark fines keeps the soil cool, which in turn keeps plant roots cool. Make sure that water can penetrate the mulch layer easily (check after watering by scraping aside the mulch and surface soil).
Tip 4: Protect your potted plants.
Potted plants also benefit from a layer of mulch. To keep pots cool – especially black plastic nursery pots that can absorb a lot of heat – place pots inside a larger ceramic pot or move the pot into a shaded location when the day is hot. Also group pots together so they shade each other, and move them into a shaded spot to ride out a heatwave. Take down hanging baskets and place them in the shade.
Tip 5: Up the watering.
Increase watering in the leadup to a heatwave – but do it at optimal times (before 10am and after 4pm) so it doesn’t evaporate in the midday heat. Always take care when turning on a hose that’s been exposed to sunlight – the water in the hose can be very hot and can scald plants. Let it run for a few minutes until the water feels cool. On hot days, water the garden in the early morning and in the evening and, if you see a plant that needs water, give it a drink whatever the time! Remember, potted plants dry out faster than plants in the soil, so they need extra water during hot times. Installing a drip irrigation system provides a reliable and simple solution for watering pots as well as the garden.
Tip 6: Apply a seaweed health tonic.
Add seaweed solution to your watering can once a fortnight – it acts as a health tonic and will help your plants become more resilient to the extremes of climate including heat. For larger areas, use a hose-on application.
Tip 7: Observe keenly.
Be vigilant for signs of heat stress and damage such as wilting or burnt leaves. Be proactive – water the plant, cover it with shadecloth or, if it is in a container, move it to a cooler shaded spot. See this article for tips on identifying heat stress in plants.
Tip 8: Time to harvest.
A blisteringly hot day doesn't have to mean you lose your hard-earned crops! Pick ripe fruit, vegetables and open flowers in the early morning if a hot day is forecast.
Tip 9: It's not just about the garden!
Think about indoor plants as well – move them away from hot sunny windows or draw the curtains or blinds to reduce potential heat damage.