Published on 06/25/09

Apply proper fertilizer for large fruit, not plant

By Sharon Dowdy
University of Georgia

Fertilizer can work wonders on plants, but applying the wrong kind to tomatoes can leave you with a tall, healthy plant with no fruit, say University of Georgia Cooperative Extension experts.

“'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. "It's like I have a crystal ball. I know right away that the gardener is using liquid fertilizer."

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.

"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.

Gardeners shouldn’t use the traditional 10-10-10 fertilizer throughout the gardening season, says Billy Skaggs, UGA Extension coordinator in Hall County.

“Once the plants are established, you need to use something with less nitrogen,” he said. “Nitrogen encourages foliage growth, and unless you are growing leafy greens, you want large fruit, not large foliage.”

The numbers on a fertilizer bag represent the mixture’s ratio. The first number represents nitrogen. The second is phosphorus. The third is potassium. For fruiting vegetables, Skaggs recommends a mixture of 5-10-15 or 6-12-12.

Using the right fertilizer mix will give you the most return on your gardening money, he said.

People are turning to vegetable gardening more and more. “I don’t know if it’s a sign of the economy or not, but it’s definitely a growing trend,” Skaggs said. “People are growing their own produce to try to help feed their families.”

Half of American families are involved in home vegetable gardening, according to the U.S. Department of Agriculture. This can range from growing a couple of tomato plants in a container to planting a “full blown” vegetable garden, Skaggs said.

“Growing a home garden is definitely economical,” he said. “For every dollar you spend -- from seeds to fertilizer -- you get an $8 return on your investment.”

Home gardens also provide readily available, more flavorful produce. “And you know it’s fresh because you picked it from your own back yard,” he said.

For more information on home gardening, contact your local UGA Cooperative Extension office at 1-800-ASK-UGA1.

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

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