Tomatoes - Tips To Avoid Their Tantrums

By Dennis Hinkamp

You’ve nurtured your tomatoes like a dog pound puppy all summer. Then when you go out to pick the first one, you discover, to your dismay, a brown, leathery, sunken area that looks like rot on the blossom end of the fruit.

“Don’t scream, pout or pull the plant out by the roots,” says Jerry Goodspeed, Utah State University Extension horticulturist. “Simply throw that particular fruit out and wait another couple of days for the next one to ripen. This is a simple case of blossom-end rot (BER). Tomatoes, squash, peppers, eggplants and melons are all vulnerable to this problem. The good news is that normally only the first few fruits to ripen are damaged.”

Blossom-end rot is technically a physiological disorder brought on by a calcium deficiency in the young fruit, Goodspeed explains. Although it is a calcium problem, it is mostly related to water imbalances and stress in the plant. Blossom-end rot can be a problem when the weather is hot and something interferes with the plant’s ability to take up and move calcium into the fruit.

Problems arise when the roots are damaged or there are excessive salts in the soil, which can include an over-abundance of fertilizer, he says. Hot weather increases the incidence of BER, as well as fluctuations in the water. Some varieties are also more susceptible than others.

Controlling BER can be as simple as reducing the watering frequency, Goodspeed says. Do not over-water tomatoes, especially in clay and heavy soils. A good mulch around the plant helps reduce water loss due to evaporation and keeps the moisture level a bit more consistent around the roots. Water deeply and infrequently.

Another cultural practice that helps reduce the likelihood of BRE is avoiding over-fertilization, he adds. Most tomatoes should only be fertilized at the time of planting. Excessive fertilizer builds up in the soil and adds to the salt content.

“Also, try to avoid damaging or injuring the roots,” Goodspeed says. “Roots can be damaged while weeding with a hoe or cultivating too deeply around the plants. Simply pull out those nasty weeds growing next to the plant. A good mulch not only will reduce water loss, but it also reduces weed growth.

“The other vegetables susceptible to BER, peppers, melons, squash and even eggplants, can be helped by the same methods that are effective on tomatoes. Of course, in the case of eggplants, nobody really cares.”

Other problems tomatoes experience this time of the year are slugs, snails and the dreaded tomato hornworm, Goodspeed says. Slugs and snails like tomatoes about as well as we do. Fruit on or near the ground is most vulnerable. They begin eating any fruit as it ripens. The best control is using some support to keep the fruit up off the ground and out of their way.


For more information, contact your local USU County Extension office.
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Issued in furtherance of Cooperative Extension work, Acts of May 9 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Robert L. Gilliland, Vice-President and Director, Cooperative Extension Service, Utah State University, Logan, Utah. (EP/08-99/DF)