How To Keep Your Plants Alive During a Heat Wave

Photo: Stocksy / Valentina Barreto
We're not the only ones who have to adapt the extreme heat. If it gets abnormally hot outside, and you don't know how to care for your plants properly, the heat will do serious damage.

Be it an indoor houseplant you keep on the windowsill, or a full-fledged wildflower garden in your backyard, how to care for your plants in a heat wave varies depending on species, climate, and temperatures. However, there are some general best practices to keep in mind that will keep your plants alive and thriving no matter how hot it gets.

The number one thing to watch out for? Water. While many native plants in southwest regions are naturally drought resistant, those that grow in rainy, humid climates are going to thirstier be during a heat wave.

Experts In This Article

Paris Lalicata, plant education coordinator at The Sill, explains that increased heat and drier climates causes outdoor plants and flowers to dry out faster than normal. "When temperatures increase around the plant, especially if humidity is low, they will drink up water at a faster rate and need to be watered more frequently," Lalicata says. "Outdoor plants will experience the same water frequency change with increased temperatures and light, so it would be good to check in on plants outdoors every few days depending on plant needs to make sure they have plenty of water."

If you're going through a heat wave, give your thirsty lil' flowers some H2O. "Watering in the early morning/evening is best to prevent overheating and loss of water through evaporation later in the day when it gets hotter," Lalicata says.

Just be sure not to overdo it—watering too much can backfire. In pots or garden troughs where drainage is essential, make sure your soil is completely dry before hosing them down again. "Over-watering isn't good for plants as it can waterlog the soil, depleting it of oxygen which causes wilting and leaf loss."

4 ways to help your plants survive the heat

1. Don't neglect your indoor plants

Depending on how well your home is insulated and air conditioned, a heat wave can affect indoor conditions, too. If you notice temps are climbing inside, your houseplants will perspire and drink water faster. Lalicata says be prepared to water more frequently inside, as well.

"It'll be best to monitor plants during times of extreme heat to see how they're adjusting and see how fast the soil is drying," Lalicata explains. "Keeping a thermometer in the home can help." Or, consider getting a moisture meter, like the 3-in-1 Moisture Meter ($12) that actively tracks hydration levels—no batteries needed.

2. Consider turning on the humidifier

Just like humans, plants can dry out too when the air gets too hot. If your indoor plants are taking up water faster during the heat wave, it might time to break out the humidifier.

"Consider incorporating a humidifier to boost water vapor in the air when temperatures are high, which will help them transpire water slower—meaning you won't actually have to water as frequently," Lalicata explains. You can also try spritzing them with a mister ($15).

3. Limit direct sunlight

If your plants are suited for direct sunlight, Lalicata says there's not really a way for them to get too "too hot"—unless temperatures around them increase to 80°F.

"Then you'll just see that they'll need to be watered more frequently, or you can move them into a cooler environment to prevent an increase in watering," Lalicata says. If you want to give indoor plants that like direct light some sun, abruptly placing them outdoors can burn or scorch them. "Placing houseplants outdoors in full to partial shade first will help prevent that transplant shock and burning."

4. Save re-potting for post-heat wave

If you need to transplant your plants—particularly your outdoor plants—hold off until temperatures return to normal. Between the extreme heat, lower water levels, and drier conditions, heat waves can stress your plants more than usual. Adding a re-potting can jeopardize their health.

Instead, Lalicata recommends waiting until after the heat wave to do any repotting or transplanting. This will make the transition a bit easier on them, ensuring better health for the long-run.

The best plants to put in every room of your house:

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