Tomato growers across Iowa are finding that this year’s unpredictable summer weather has created plenty of challenges in the garden.
From split fruit to damaged leaves and tomatoes that fail to develop, gardeners may be seeing several different symptoms on the same plants. Iowa State University horticulture and plant health specialists say weather-related stress is responsible for many of the problems showing up in home gardens.
Periods of heavy rainfall followed by heat and dry conditions can put tomato plants under significant stress. Rapid changes in soil moisture can contribute to blossom end rot, while sudden increases in water uptake may cause ripe or developing tomatoes to crack.
Another problem gardeners may notice is sunscald. Tomatoes that become exposed to intense sunlight can develop pale or discolored patches. This is more likely when foliage has been lost to storms, disease or excessive pruning.
Hot temperatures can also interfere with pollination. When temperatures remain high, tomato blossoms may drop before fruit develops. Fruit production often improves once temperatures become more moderate.
Wet and humid conditions can create additional problems by encouraging diseases such as early blight, Septoria leaf spot and bacterial spot. Keeping foliage as dry as possible, spacing plants properly and removing diseased plant material can help slow the spread.
Gardeners can reduce many of these problems by taking a consistent approach throughout the growing season. Deep, regular watering, a layer of mulch, balanced fertilizer and good air circulation can help plants better withstand changing weather conditions.
While not every tomato problem can be prevented, maintaining healthy plants and avoiding major swings in moisture can give Iowa gardeners a better chance of finishing the season with a strong harvest.
Source: Iowa State University Extension and Outreach, Iowa State University Plant and Insect Diagnostic Clinic.
