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Michael Wheeler: How to prevent tomato problems
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Even though fresh ripe tomatoes are just now coming in, our office has been getting questions about problems with tomatoes.

Since most tomato problems are easier to prevent than to cure, now is a good time to review potential problems and their prevention.

BLOSSOM-END ROT

Blossom-end rot is a serious problem of ripening tomatoes. As the fruit ripens, the blossom end turns dry, brown and leathery. The spot is sunken and these tomatoes can ripen before others.

This is caused by a calcium deficiency in the fruit. It can be prevented by control of soil nutrition and consistent watering.

FRUIT CRACKING

Fruit cracking can be caused by periods of fast growth during times of high temperature and moisture supply or rain after a dry period.

Not all cracking can be avoided, but you can lessen its severity by mulching and maintaining an even water supply.

CATFACING

Catfacing is a condition in which the fruit is malformed or irregularly shaped often with brown scars at the blossom end and sometimes running up the side of the fruit. The blossom end of the fruit will be puckered with deep crevices.

This is caused by cool temperature at the time of pollination and early growth. Some varieties are more susceptible than others.

The only control is to use resistant varieties, to plant later or to use plastic or row covers to increase temperature on cool days and nights.

Catfacing does not affect the edibility of the fruit. Just cut off the scars and eat the rest of the tomato. It usually only affects the earliest fruit set.

LEAFROLLING

This often occurs after fruit set when the plant was heavy with a load of fruit. Leafrolling most often begins on the older leaves and moves up the plant.

Wet soils can also cause leafroll.

The condition is harmless and should not hurt the final production.

UNEVEN RIPENING

Uneven ripening can be caused by several factors including nutrition, high temperature and disease.

The most common problem is probably nutrition. High nitrogen levels and low potassium levels can cause uneven ripening. One wall of one portion of the tomato will remain gray or white after the rest of the tomato turns red.

The best control is to take a soil sample and fertilize accordingly.

SUNSCALD

This condition appears as a white blistered area on the top of the tomato. The area can turn leathery and be invaded by rots.

To control, do not prune heavily and maintain nutrition and pest control to provide a good leafy cover for the tomatoes.

BLOSSOM DROP

Blossom drop occurs wherever temperatures exceed or are less than a certain optimum range. Although this range varies with tomato variety, the night temperature should be between 55 and 75 degrees for the best blossom set.

Certain varieties are sold as “coldset” or “hotset” varieties and will set fruit more consistently at the extremes of this range.

The only good thing about this dry weather is there have been very few cases of diseases such as late blight. But with afternoon showers, this can change.

If you run into any problems with your vegetable garden, come by the office and we can help you figure out what is going on.

Michael Wheeler is county extension coordinator for the UGA Cooperative Extension office in Hall County. You can contact him at 770-535-8293, www.hallcounty.org/extension. His column appears biweekly and on www.gainesvilletimes.com.

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