Protect Your Garden During Extreme Summer Heat

By Scout Nelson

Extreme summer heat places significant stress on home gardens and reduces the growth of many vegetables. High temperatures affect flowering, pollination, fruit development, and overall plant health. Gardeners can reduce these problems by using proper watering and plant care practices during hot weather.

Tom Kalb, Horticulturist, NDSU Extension, explained that extreme heat affects many common garden crops. Cucumber and zucchini plants may wilt during the afternoon, produce fewer female flowers, and experience poor pollination. Bees also become less active in very hot weather, leading to fewer fruits and more misshapen vegetables because flowers are not fully pollinated.

Tomato plants also struggle when daytime temperatures remain above 85 degrees Fahrenheit. Flowers may drop before producing fruit, while tomatoes already on the vine ripen more slowly.

Dry soil conditions also reduce calcium movement into developing fruits, increasing the risk of blossom end rot. Pepper plants may develop sunscald when fruits are exposed to direct sunlight because the plants do not have enough leaves to provide shade.

Gardeners can help plants by providing shade during the hottest part of the day. Shade cloth works well for garden beds, while container plants can be moved into shaded locations. Applying clean straw or untreated grass clippings around plants also helps conserve soil moisture and keeps roots cooler.

Proper irrigation is one of the most important ways to reduce heat stress. Plants should receive deep watering instead of small amounts every day. Deep watering encourages roots to grow farther into the soil, making plants more tolerant of dry weather.

Morning irrigation is the best choice because plants absorb water before temperatures rise and leaves dry quickly. Watering during the middle of the day wastes water through evaporation, while evening watering leaves foliage wet for long periods, increasing the risk of plant diseases.

Gardeners should also avoid overhead watering whenever possible. Plants absorb most of their water through their roots, not their leaves. Using watering wands, drip irrigation, or soaker hoses delivers water directly to the soil while keeping leaves dry and reducing disease problems.

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