Weather Challenges Impact Vegetable Gardens and Crop Quality

By Andi Anderson

Weather conditions such as extreme heat and irregular rainfall can cause serious issues in vegetable gardens, even when insects or diseases are not present. Iowa State University Extension and Outreach specialists offer useful advice to help manage these weather-related challenges.

Aaron Steil, horticulture specialist, explains that when daytime temperatures go above 90°F or nighttime temperatures exceed 75°F, crops like tomatoes, peppers, and beans may drop their blossoms before pollination. This blossom drop reduces yield.

Warm temperatures also slow ripening in vegetables like eggplant and tomatoes, keeping fruit green for longer. Cool-season crops such as lettuce, peas, and spinach may stop growing in hot conditions. If soil temperatures go above 86°F, potato tubers stop forming altogether.

High heat affects pollination too. Cucumbers and squash may develop uneven or misshaped fruit due to poor pollination. Hot weather can also change the flavor of vegetables. Cucumbers might taste bitter, and crops like carrots and melons can lose their sweetness because sugars break down faster in the heat.

To help reduce plant stress, Steil suggests watering deeply once a week during dry periods. This supports strong root systems. Adding mulch around plants lowers soil temperatures and limits water evaporation.

Heavy or inconsistent rainfall creates more challenges. Tomatoes may crack due to sudden growth during hot, sunny days. Cabbage heads can split from taking in too much water quickly.

One common issue from moisture imbalance is blossom end rot, especially in tomatoes, squash, and peppers. This appears as a black or brown spot on the fruit's base and results from poor calcium uptake caused by soil moisture changes.

To prevent such problems, maintain steady soil moisture using deep watering and mulch. Damaged fruits with no rot are still edible but should be used soon as they spoil faster.

Consistent care helps gardeners protect their plants and enjoy better harvests despite difficult weather.

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