A run of unusually hot days does to houseplants in summer roughly what a cold snap or power outage does in winter — it’s a short-term emergency that calls for a different response than normal seasonal care. The goal during a heatwave isn’t optimizing growth, it’s getting plants through the worst of it without losing leaves or, in bad cases, the whole plant.

How hot is actually dangerous

Most common tropical and subtropical houseplants start to struggle once temperatures climb above roughly 85-90°F (29-32°C), and the risk compounds fast if humidity is also low or the plant is sitting in direct sun. Leaves can wilt, scorch, or crisp at the edges well before the room itself feels unbearable to you, especially for anything already sensitive to dry air or inconsistent watering. Just as glass makes a cold snap worse for a plant pressed against a window, it also makes heat worse — a spot that’s pleasant in spring sun can turn into a small greenhouse during a heatwave.

Move plants back from hot windows

Direct sun through glass during a heatwave can scorch leaves that would be perfectly fine with the same light on a cooler day, since the glass traps heat and pushes the immediate air temperature well above the room average. Pull sun-exposed plants back a few feet, or hang a sheer curtain to filter the light, for the duration of the heat. A few days of slightly dimmer light is a minor tradeoff compared to scorched, irreversibly damaged leaves.

Adjust watering, but don’t overcorrect

Soil dries out much faster in high heat, so check it more often than you would on a normal schedule rather than sticking to your usual routine — see watering houseplants the right way for judging by feel instead of the calendar. Timing matters too: watering in the cool of early morning or evening, rather than the heat of midday, reduces stress and gives water more time to soak in before it evaporates. That said, checking more often isn’t a license to overwater — a plant that’s wilting from heat stress doesn’t always need more water, so confirm the soil is actually dry before adding more. See the best water for houseplants if you’re also dealing with warm tap water, which cools plants less effectively than water at room temperature.

Watch humidity and airflow

Heat combined with air conditioning or a hot, dry outdoor breeze can crash humidity fast, adding a second stressor on top of the temperature itself for plants that like moist air. Grouping plants together, misting, or running a humidifier can help offset the drop — see how to increase humidity for houseplants for specific methods. Some gentle air circulation helps too, since stagnant hot air sitting around a plant is worse than the same temperature with a little movement — a fan on low nearby is enough; avoid pointing it directly at the plant, which just accelerates moisture loss from both the soil and the leaves.

If a plant is already heat-stressed

Wilting, crispy leaf edges, or pale, scorched patches mean the damage is already underway. Move the plant out of direct heat and sun immediately, even if that means a temporarily worse spot for light. Resist the urge to respond to wilting with a heavy watering right away — wilting from heat stress isn’t always a watering problem, and soaking already-stressed roots can make things worse. Give the plant some time in better conditions before deciding whether any damage is permanent; a lot of heat stress is recoverable once temperatures drop, similar to how curling leaves from heat or light stress often relax again once conditions improve.

After the heatwave passes

Once temperatures return to normal, resume your regular watering and feeding schedule gradually rather than all at once — a heat-stressed plant needs a little time for its roots and leaves to recover before it can make full use of water and nutrients again. Trim away any leaves that are clearly dead or irreversibly scorched, but wait a few days before cutting anything borderline, since tissue that looks rough right after a heatwave can sometimes partially recover once the plant is back in stable conditions.