Published on 06/28/06

Beautiful, fruitless plants

By Sharon Omahen
University of Georgia

When it comes to growing prizewinning tomatoes, it's the size of the fruit, not the plant, that counts.

As summer gardening season heats up, University of Georgia Cooperative Extension specialists are answering the most common tomato-growing question: How can my tomato plants be 8 feet tall and not produce any tomatoes?

"That's the question I answer the most," said Bob Westerfield, a UGA Extension consumer horticulturist with the UGA College of Agricultural and Environmental Sciences. "It's like I have a crystal ball. I know right away that the gardener is using liquid fertilizer."

Liquid's hard to calibrate

Westerfield says it's very easy to give your tomatoes and other garden vegetables too much of a good thing when you use liquid fertilizers, like the ever-popular Miracle-Gro. Liquid fertilizers are hard to calibrate, and they're absorbed into the plant very quickly, he said.

"Too much nitrogen will cause the plant to put out incredible growth but hold back on reproducing," Westerfield said. "You want the plant to reproduce, because that's where the fruit comes from. Too much fertilizer will also cause the blooms to abort. And no blooms means no tomatoes."

The key to growing tomatoes, he said, is to fertilize at planting and not again until the plant produces dime- to quarter-sized fruit.

Diseases cause problems, too

The other common tomato problem Westerfield gets questions on is blossom end rot. "In this case, people call in a panic because their tomatoes are turning black on the ends," he said.

Blossom end rot is a sure sign of a moisture or water problem in your home garden. "Usually it occurs when there's a lack of water when the fruit is forming," he said.

Blossom end rot can also be a sign of low calcium in the plant. Westerfield recommends treating the plants with dolomitic limestone and watering plants evenly.

When it comes to diseases and viruses, prevention is the best cure. The best preventive measures, he said, include planting disease- and pest-resistant varieties and using sound cultural practices.

If, despite your best efforts, your tomato plants become infected, Westerfield's advice is simple and direct. Pull them up and get rid of them.

Hands-on research

To make sure he's ready for each season's vegetable diseases and conditions, Westerfield plants a home garden and a work garden. The home garden provides fresh vegetables for his family. The work garden is for research and provides fresh vegetables for the local food pantry.

"My work garden is a kind of trial garden," he said. "As a UGA consumer horticulturist, I want to be ready for home gardeners' questions. I test new varieties, too, in case something pops up I'm perplexed by."

Besides tomatoes, he plants the most commonly Georgia-grown vegetables including green beans, okra, cucumbers, squash, peppers, corn, pumpkins and potatoes. He also grows winter crops like broccoli, cabbage, collards and cauliflower and spring crops like lettuce and carrots.

"A side benefit to my research garden is the produce we donate to the Five Loaves and Two Fish Pantry near the UGA Griffin campus," he said. "Most of the people who get these vegetables are really needy and don't have the resources, or the knowledge, to plant a home garden. Fresh vegetables are welcome treats from the canned foods they typically get through the pantry."

UGA Master Gardeners statewide donate a portion of their harvests to the needy through the Plant-a-Row for the Hungry program.

"Plant-a-row generates thousands of pounds of vegetables that are donated to pantries across the state," Westerfield said. "My garden is just a small piece of this program."

Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.