Follow these tips and your tomatoes will thank you (and so will your tastebuds)

Wednesday, July 25, 2007 | 12:00 a.m. CDT; updated 5:53 a.m. CDT, Tuesday, July 22, 2008

Most of my husband’s relatives know I’m a Master Gardener and have a few questions for me every time we get together.

And it was no different recently when we attended a family reunion. This trip, most of the questions centered around tomatoes. Since my own tomato plants are getting tall, flowering and beginning to develop fruit, this might be a good time to write about how to care for tomato plants.

Pruning is important for tomato plants to ensure larger, more uniform fruit production as well as quality.

The parts of a plant are the flower clusters, the main stem, side shoots or suckers, and leaflet branches attached to the main stem. When pruning a tomato, pinching out the sucker is the goal. The sucker grows at the attachment of the leaflet branches to the main stem. Pinch the suckers off when they are about four inches, leaving the leaflet branches intact.

The best time to prune is early in the growing season. Pinch off suckers every week. When the tomato plant begins to set fruit you can cut back to every few weeks. A word of caution: Bush tomatoes should not be pruned.

I don’t have a large area where I grow tomatoes, so when my plants get beyond stake height I start pinching out the top. This allows for larger fruit.

The advantage to letting them continue to grow is that the plant will send out shoots that will fall over, set fruit and provide a little shade for earlier set fruit. It isn’t very neat and some of your tomatoes will be in the dirt.

Tomatoes are heavy feeders so fertilizing is helpful. If used when preparing the soil, choose one low in nitrogen (N), high in phosphorous (P) and medium-to-high in potassium (K). Look for ratios like 8-32-16 or 6-24-24. After the tomatoes begin to grow they should be side-dressed during the growing season. These fertilizations should be with ammonium nitrate (N). (The reason it isn’t recommended to use a high ratio of nitrogen early when the plant is growing is that it will cause the plant to produce lots of leaves and little fruit.) The first side-dressing should be when the fruits are about one-third the size they will become and the second should be a few weeks after picking the first fruits. Make the last side-dressing a month later. Water these dressings well into the ground.

Tomatoes should have one inch of water per week in May and June and at least two inches per week in July through September. Plants in containers may need watering every day. When the plant is wilted, it is stressed and more prone to disease. Water deeply so that the root system is strong.

Frequent, light watering encourages weak roots, resulting in easily diseased plants.

A few common problems with tomatoes are blossom-end rot, cracking, sunscald and cloudy spots.

Blossom-end rot occurs on the blossom end of the fruit as a dime to half dollar-sized, brownish, concaved rotted area. It is usually caused by calcium deficiency or irregular moisture. Tomatoes that appear cracked can also be the result of irregular watering. It also is more common in some varieties, so choosing a crack-resistant variety is useful.

Sunscald and poor color are the result of high temperatures and direct exposure to the sun. Over-pruning can affect this, if too many shading leaf clusters are removed and the fruit is too exposed.

Cloudy spots are irregular whitish spots under the skin and are caused by stink bugs feeding on the fruit during its development.

Enjoy home-grown tomatoes. There is nothing like them for flavor.

For further information on growing and caring for tomatoes contact your MU Extension office. There are several MU Guides published that give greater detail about the above topics and others about growing vegetables.

Tammy Bush has been a Master Gardener of four years. She has been a pediatric nurse and educator, but she now works from home as chauffeur to her two teenage sons. Two cats and a husband round out her life. When she isn’t driving, she runs a quilting business, putters in her gardens and likes do-it-yourself yard and home projects. Shade gardening, recycling and Japanese gardens are a few of her favorite things. She can be reached at

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