Learn how to protect plants from extreme heat using smart watering and shade cloths to keep gardening during a heat wave.
Smart Watering
Water early in the morning when moisture evaporates more slowly. Check soil daily and water if it’s dry 2 or 3 inches below the surface. It’s better to soak the soil every few days than dampen only the surface daily.
Mold soil into ridges around plants to create bowls to water into. That way, water will be held in place to soak in rather than running away over the soil surface. Alternatively, water into old pots or bottles sunk into the soil next to plants.
Consider using a drip irrigation system on a timer if you’re unable to water daily in hot weather.
Container plants may need watering more than once a day, especially if it’s windy. Make sure the water is being absorbed into the potting soil, and not simply pouring down cracks between the potting soil and container wall. Keep pouring until you see water running out of the bottom. Use pot saucers to retain the water for longer.
I outline 10 more smart-watering tips here.
Reduce Evaporation
Lock in soil moisture by mulching after watering using organic material, such as compost, leaves or grass clippings. This will help slow evaporation by shading the soil and keep the root zone cooler.
It will also help to plant densely or use vigorous sprawling plants like squashes to create a living mulch that will shade the soil.
Stop Fertilizing
Temperatures above 85 to 90 degrees Fahrenheit can cause plants to roll up their leaves to reduce water loss, drop their flowers or stop producing new ones.
At this point, it’s best to stop fertilizing, because plants need even more water to process fertilizer. Adding nutrients also prompts the plant to grow more, which is stressful to the plant in hot weather.
Provide Shade
Shade plants with shade cloth or with fabric such as tulle or old bedsheets. Plants will grow more slowly under it, but they’ll be less stressed. Support the shade cloth by pinning or clamping it onto frames or hoops.
Cool-season vegetables, such as cabbage and lettuce, and fruits such as strawberries, will particularly benefit from shading from hot afternoon sunshine.
Harvest
Harvest fruits or leaves promptly to help conserve your plant’s energy. Finish ripening fruits such as tomatoes that haven’t fully colored up in the kitchen to give your plants a break. Plants might slow down in hot weather, but they’ll return to productiveness once the weather cools.
More on How to Protect Plants from Extreme Heat
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Benedict Vanheems is the author of GrowVeg and a lifelong gardener with a BSc and an RHS General Certificate in horticulture. Read all of his MOTHER EARTH NEWS posts here.
