Most of us have experienced the horror of coming home to withered flowers, lifeless, droopy leaves or a blanket-of-brown in the garden during the blistering heat of an Australian summer. Heat exhaustion can catch us out after weekends away or sudden heat waves and make our tranquil tropical landscapes look more like moonscapes. But it doesn’t have to be this way!
In this blog we’ll explore ways to see the signs of heat stress and take action, plus offer some top tips to prevent your plants from dying on those scorcher days.
Learn to Recognise Stress
One of the best ways to keep your plants alive on scorcher days is knowing how to spot problems before they take hold and ravage your garden. Signs of stress during summer months or heat waves usually have to do with too much heat and not enough water.
What to watch out for:
foliage that’s typically bright green or vibrant looking pale
tender leaves of tropical plants wilting with exposure to too much heat
sunburn can often look like a rough brown or yellow patch on leaves/stems. Think ‘crispy’ when it should be lush! It can also present as discoloured darker areas on leaves.
flowers and leaves dropping off or yellowing can be a sign a plant is stressed.
Don’t be tempted to water your plants in the middle of the day. The water droplets turn into mini magnifying glasses on the leaves and intensify the heat.
Tip: Plants can sometimes need a cool down. Do that when the heat of the day eases in the afternoon or evenings.
Plants can get a bit lazy keeping their roots near the surface if they only get water for five minutes every day. So, go deep! Deep watering at the base of the plant for a long time is the best way to revive and protect plants. By watering more deeply weekly, you’re training the plants to send their roots deeper in the soil where the water is.
Typically, it’s best to water most plants once a week. How long you water for depends on your soil type, but long enough to saturate the soil about one foot down. Vegetables might need deep watering more frequently when it’s really hot.
Tip: When you know a heat wave is on the way, prepare by watering deeply at ground level at night, when the air is cooler. You can also bury some buckets/pots with holes in them and fill and refill during a watering session to get further down.
Set up Shade
Just like people and animals, plants will thrive more with some shade. If you don’t have shade cloth around, a big beach umbrella works well too. Planting hedging and screening plants can also help create shaded areas in your garden. Get creative with some old bed sheets, or even propped-up cardboard to give your plants a break from the scorching sun.
The trick is to make sure your shade set up allows air to circulate well around the plants.
Tip: If the only cloth you have around is dark coloured, it will absorb heat and any foliage could be scorched from it, so keep it far enough away to prevent burning.
If you have a lot of pot plants that are struggling in the heat, group the indoor plants together, water them deeply, then place them on a wet towel in either the bathtub, shower base or laundry tub. The combined humidity will help keep them alive. For the outdoor plants, group them in the coolest, shadiest part of your garden or rig up shade and repeat the same method of creating a microclimate and watering them well.. but not too well! Read on!
Perfecting the Balance with Pot Plants
Avoid dark-coloured pots as they attract and retain more heat than lighter ones and can actually fry a plant’s roots! Try putting potted plants inside larger pots to give them some insulation and shade, while making to have good drainage.
Balance is Everything: Don’t overwater! Drainage is essential for a pot plant to thrive and overwatering at any time is guaranteed to kill them off in record speed. Pot plants (and non potted) will sometimes wilt from the severe sun, even when they have enough water, so test the soil with your finger before you water. If a pot feels heavy and/or the soil feels damp an inch or so under the ground, your plant probably doesn’t need more moisture.
Tip: Plants drown in standing water, even when it’s hot. Don’t overwater!
Step Away from the Fertilizer
Thinking about fertilising and it’s a blast furnace outside? Forget it! Root systems struggle during high temperatures. Trying to absorb fertilizer can be like sticking your plant in an inferno. Ouch! Composting is still okay.
Don’t Remove Damaged Foliage
Tempting though it is to remove the ugly result of the heat, all the brown leaves and branches provide protection against additional damage and could actually be harbouring living tissue, so hands off the pruners, at least for now.
With a little bit of prior preparation when you know major heat is coming or some quick action, you can do a lot to prevent total disaster and keep your plants alive. Whether it’s rigging up some temporary shade, moving your precious potted plants to cooler climbs (indoors and out!) or a bit of deep watering we hope these tips will keep your garden thriving.
Plant to suit your Location
A final word of caution to prevent catastrophic plant deaths is to plant hardy native plants and/or those suited to your location, such as robust tropicals and heat tolerate varieties like succulents. If you plant varieties in hotter locations (like most of Qld) that are more comfortable in cold climates, they will be much harder to keep alive during testing times.