By Aaron J. Steil
Not all problems in the vegetable garden are caused by insect pests or diseases. Hot temperatures and heavy or inconsistent rainfall can lead to deformed fruit and low yields. Iowa State University Extension and Outreach horticulture specialists discuss common weather-related issues in the vegetable garden and offer tips for managing them.
According to Aaron Steil, consumer horticulture extension specialist, high temperatures, particularly those above 90°F during the day or 75°F at night, can cause blossom drop in crops such as tomatoes, peppers and green beans. Flowers may fail to form or fall off before pollination, leading to reduced yields.
“Temperatures above 85°F can delay ripening in vegetables like tomatoes, peppers and eggplant, causing fruit to remain green longer. Cool-season crops like lettuce, spinach and peas often stop growing altogether,” said Steil. “While soil is typically cooler than the air temperature, if it exceeds 86°F, potato tubers stop forming. Heat also causes incomplete or poor pollination in vine crops like cucumbers and squash, resulting in misshapen produce.”