How to Keep Your Plants Healthy and Cool in a Heatwave
It happens every year. One minute, you’re enjoying a little extra sunshine on your windowsill; the next, half your plant gang is struggling, and you find yourself Googling “crispy fiddle leaf” for the third time that week.
Ours summers are becoming increasingly erratic in the UK. In Northern Ireland, in particular, we can have scorching hot Mays, then a stormy August, then hot sun again in September.
What this means for our houseplants is constantly fluctuating heat.
When the temperature soars, even the hardiest houseplants start to look a little weary. Don’t panic, a few simple strategies can help your indoor jungle weather the heat.
Keep Your Plants Out of Direct Sunlight
You may think your plants will be delighted to see the sun. But that's only true of a few houseplants.
Most houseplants love bright light, but usually bright indirect light.
Indirect light means brightness but not direct sun rays. North facing windows will have no direct sunlight. South facing windows will have direct sun for the majority of the day. This is where you should put succulents and cacti.
East facing windows will get that sun in the morning, but it won't be as powerful. West-facing will get the very hot afternoon sun. So for plants placed here, you may need to move them further away from the window or have a sheer curtain protecting them.
Getting plants in the right place will help prevent leaf scorch and wilting. They don't have sun-cream like you, so you will have to protect them.
Water Wisely
Summer heat makes watering feel urgent, but more isn’t always better. Overwatering can lead to root rot, especially if the soil can’t dry out. Water first thing in the morning or during the cooler hours of the evening, never in the midday swelter. Pour slowly and deeply so moisture reaches the roots, and always tip away any leftover water from trays or saucers.
Our tip is to always stick your finger into the soil. If it’s dry a couple of centimetres down, it’s time for a proper soak. If not, wait, overwatering in the heat can suffocate roots just as quickly as drought.
Turn Up Humidity and Place Trays of Water Nearby
When the air dries out, so do your plants, especially tropical varieties like Calatheas, Ferns, and Alocasias that love muggy air. Create a “humidity bubble” by grouping plants close together. For an extra boost, place pebble trays filled with water beneath their pots, just make sure the pots’ bottoms aren’t submerged. Misting in the early morning can help, but don’t drench the leaves, and definitely skip it after dark or in blazing sun.
Don’t Feed or Repot Right Now
While it might be tempting to feed your plants extra during drought or high heat, heatwaves usually slow plant growth, so a break from feeding is the safer option. Hold off on fertiliser or major repotting projects until things cool down. It’s tempting to go into rescue mode, but roots fare much better left in peace during stressful weather.
Keep an Eye Out
Look for droopy, curling, or pale leaves, these are your plant’s SOS signals. Sometimes a move out of the sun or a little extra humidity is all that’s needed. Snip off any crispy leaves to help focus your plant’s energy on fresh growth. Don’t stress over a brown spot or two; most plants bounce back with a little patience and care.
A Summer Routine That Works for You
Set reminders if you tend to forget, tweak your watering routine, and treat yourself, and your plants to a relaxed, not frantic, rhythm. And if you’re heading away for a long weekend, gather pots together in a cool, shaded spot and give them a generous watering before you go.
Every heatwave ends eventually. You’ll find that when cooler days return, your efforts pay off, shiny leaves, happy roots, and maybe even a new shoot or two as a thank-you.
If you need any advice or want to talk through a plant dilemma, pop into The Green East in Belfast.
We’re always here to help you keep your houseplants thriving, no matter what the weather’s doing outside.