It’s one of those humble-brag type of problems in the garden: Oh look, we’re having this crazy heat wave with wonderfully warm summer weather. What do I do?
While you’re grateful for the nice weather, it’s easy for your plants to take an absolute beating when the temperatures soar high above average. Here’s a few strategies to cope.
Disclaimer: I garden in zone 3b in the Canadian Prairies. What is hot for me might be normal for you. If you live in the Southern States and have some other solutions for surviving a heat wave, I would LOVE to hear them in the comments, as you are the experts!
Disclaimer 2: This post contains affiliate links, which means I earn a bit of extra coffee money, at no extra cost to you, if you purchase anything from one of my links. Thanks for supporting Shifting Roots!
Water, and Water Some More
Now is not the time to be slack with your watering! Water early in the morning for best results. Evening is okay too. Watering in the afternoon is not ideal, but it’s better than no water at all if that’s the only time you’re able to water your plants.
P.S. That whole old wives tale about the water scorching your plants if you water in the afternoon? It’s a myth. Afternoon watering is only bad because more of the water will evaporate, leaving less for the plants.
Surround Your Plants with Mulch
A two inch layer of shredded newspaper, compost (like the kind you buy in bags at the store), wood shavings, or straw go a long way to keeping moisture in and the soil cool.
Related: How to Use Mulch in the Garden
Move Containers to the Shade
Containers looking sad? Move them to an area that gets afternoon shade until the heat wave is over. Make sure you water all containers at least once a day, and check on smaller containers to see if they need an extra watering in the evening.
Fun fact: plants that are planted close together, like those in a square foot garden, act as a living much for each other and provide shade to each other’s leaves. This helps them survive a heat wave with not as much intervention.
Use a Shade Cloth
While you can move your containers, you can’t move your garden. If your plants are suffering, set up a shade cloth for them during the hottest parts of the day. You can purchase one like this, or drape a large white sheet over your plant.
Just be sure to have some sort of frame or support system so your plants don’t get crushed.
Expect Cool Weather Loving Vegetables to Bolt…
Growing broccoli, cauliflower, lettuce, or spinach? Expect them to bolt during this hot weather. If you see the heat wave coming, try and harvest what you can from them before it hits.
…and Flowering Vegetables to Stop
Tomatoes, peppers, and other vegetables will simply stop flowering when the temperatures get too high. There’s nothing you can do about it, just know that the flowers might fall off and you didn’t do anything wrong.
Do Not Fertilize in a Heat Wave. . . until it’s Cooler
Whatever you do, don’t fertilize your plants. Any fertilization at this point is just going to stress out your plants and do more harm than good. Wait until temperatures return to normal or cool down a bit.
Pick Ripe Vegetables to Reduce Stress
Did you know that it takes 3 to 4 more times energy for a plant to keep on a ripe vegetable than it does to encourage the plant to grow a new one? If you know a heat wave is coming, do your plant a favour and pick off any ripe or almost-ripe veggies before it hits.
For best harvest, especially for things like lettuce that can wilt, harvest in the early morning.
Want to Start a Vegetable Garden?
Learn the basics in just a few minutes, and set up your first garden in a day or less!
Get just the basics you need to start your garden this spring. I'll also email you a mini email course, helpful tips and easy garden advice, straight to your inbox.
Ready to start your garden adventure?
Kristen is a former farm kid turned urban gardener who owns the popular gardening website, Shifting Roots. She is obsessed with growing flowers and pushing the limits of what can be grown in her zone 3b garden. She also loves to grow tomatoes, but oddly enough, dislikes eating them raw.