The thermometer is rising, the soil is cracking, and your plants are showing signs of distress. Don't panic — with the right actions, your garden can survive a heatwave without major damage.
1. Water smartly, not more
The classic mistake during a heatwave is watering in the middle of the day. The water evaporates before even reaching the roots, and droplets on leaves act like small magnifying glasses that burn the foliage.
The golden rule: water early in the morning (before 9am) or in the evening after 6pm, directly at the base of plants. Prefer deep and less frequent watering — it's better to water abundantly twice a week than a little every day.
⚠️ What not to do
Watering leaves in full sun. This causes burn spots and promotes fungal diseases. Always aim for the base of the plant.
2. Mulch to retain moisture
Mulching is your best ally in summer. A 5 to 10 cm layer of organic matter (straw, wood chips, dead leaves, plant shreddings) at the base of your plants can reduce water evaporation by up to 70%, protect roots from heat, and limit weed growth.
Flax or wheat straw
Light and economical. Ideal for vegetable gardens and flower beds.
Wood chips
Durable, aesthetic. Perfect under shrubs and fruit trees.
Shredded dead leaves
Free and ecological. Decomposes while nourishing the soil.
Dried grass clippings
Very effective in thin layers. Needs regular renewal.
3. Shade the most fragile plants
Not all plants tolerate the same light intensity. Young plants, seedlings, lettuces and leafy vegetables suffer particularly above 30°C. A shade cloth (50 to 70%) stretched above crops can lower the perceived temperature by 5 to 8 degrees.
Garden umbrellas, wicker screens or even old white sheets can help while waiting for specialized equipment. The goal is not to deprive plants of light, but to filter the most aggressive rays between noon and 4pm.
4. Watch for signs of water stress
Learn to read your garden. Here are the warning signs to observe each morning:
- Leaves curling or rolling up on themselves
- Stems drooping despite moist soil (pure heat stress)
- Yellowing or browning of leaf edges
- Premature drop of flowers or young fruits
- Hard, cracked soil pulling away from pot edges
🪴 For potted plants
They are much more vulnerable because their soil volume is limited. During a heatwave, daily watering may be necessary. Group pots in the shade and place water-filled saucers under the most sensitive ones.
5. Adapt your garden care
A heatwave is not the time for severe pruning, repotting or nitrogen fertilization. These interventions stress the plant when it's already weakened. Wait for temperatures to return to normal.
However, you can safely remove faded flowers and dead leaves to limit the plant's energy expenditure, and lightly hoe the soil to break the surface crust that prevents water from penetrating.
🌱 In summary
Water early in the morning aiming at roots, mulch generously, shade fragile plants between noon and 4pm, and avoid any stressful intervention while the heat persists. With these precautions, your garden will come out of the heatwave in much better shape than you expected.
