How to Protect Houseplants During a Heatwave
Extreme heat can wilt, scorch, and dehydrate houseplants fast. Learn how to shade, water, and cool your plants to get them through a heatwave without lasting damage.
When temperatures spike well above 90 F, even heat-tolerant houseplants can suffer. Soil dries in hours, leaves wilt and scorch, and plants near hot windows can effectively cook. A heatwave demands a different response than ordinary summer care.
The goals during extreme heat are to keep plants hydrated, shield them from intense direct sun, and lower the temperature around them. With a few quick adjustments you can carry your collection through a heatwave and avoid the lasting damage of crisped leaves and dehydrated roots.
Step by step
- 1Move plants out of direct sun
Pull plants back from hot south- and west-facing windows and relocate the most vulnerable ones to a cooler, shadier room during the heatwave.
- 2Block the harshest light
Close blinds or hang sheer curtains during the hottest hours to cut the intensity of direct sun and the heat radiating through glass.
- 3Water in the early morning
Check soil more often and water thoroughly when the top inch is dry, watering at dawn so plants are hydrated before peak heat.
- 4Raise humidity around plants
Group plants together and set pots on pebble trays with water to create a more humid microclimate that slows water loss through leaves.
- 5Increase airflow
Run a fan near the plants to help them cope with heat, making sure it circulates cooler indoor air rather than blowing hot air on them.
- 6Hold off on feeding and repotting
Pause fertilizer, repotting, and other disturbances until the heat breaks, since stressed plants cannot recover from added strain.
Why heat stresses plants
In extreme heat, plants lose water through their leaves faster than their roots can replace it, leading to wilting even when the soil is still slightly moist. Prolonged heat can cause leaf scorch, crispy edges, and dropped leaves, and in severe cases the roots can be damaged in pots that overheat.
Plants pressed against sun-facing glass are at the highest risk, since window glass magnifies heat and light. Plants in small or dark-colored pots also suffer, because the limited soil volume heats up and dries out quickly.
Shade, cool, and hydrate
The most effective move is to reduce direct sun. Pull plants back from hot south- and west-facing windows, close blinds or hang sheers during the hottest part of the day, and move the most vulnerable plants to a cooler, shadier room. Increasing airflow with a fan helps plants cope, as long as it is not blowing hot air directly on them.
Hydration is critical, but do not drown plants. Check soil more often than usual and water thoroughly when the top inch is dry, ideally in the early morning. Grouping plants together and using pebble trays raises local humidity, which eases water loss through the leaves.
What not to do
Resist the urge to overcompensate. Do not soak a plant repeatedly just because it looks wilted; afternoon wilting with moist soil is heat stress, not thirst, and overwatering hot, stressed roots invites rot. Do not fertilize during a heatwave, since feeding stressed plants can burn already-strained roots.
Avoid repotting or any other disturbance until the heat passes. A stressed plant has no energy to recover from root disruption. Hold off on big changes and focus only on shading, cooling, and steady hydration until conditions return to normal.
- Afternoon wilting with still-moist soil is heat stress, not thirst; do not add more water.
- Move plants away from hot electronics and appliances that add ambient heat.
- Light-colored pots stay cooler than dark ones in direct sun.
- Succulents do not need extra humidity; focus cooling and shading on tropicals.
FAQ
Should I water more during a heatwave?
Check the soil more often and water when the top inch is dry, ideally in early morning. But do not repeatedly soak a plant just because it wilts; afternoon wilting with moist soil is heat stress, and overwatering hot roots can cause rot.
Why is my plant wilting even though the soil is wet?
In extreme heat, plants lose water through their leaves faster than roots can supply it, so they wilt despite moist soil. This is heat stress. Move the plant to a cooler, shadier spot rather than adding more water.
Can I fertilize my plants during a heatwave?
No. Avoid fertilizing during extreme heat. Stressed plants cannot use the nutrients, and feeding can burn roots that are already strained. Wait until temperatures return to normal and the plant has recovered.