Blackwelder column: What's wrong with my tomatoes?

Saturday, July 04, 2009 3:00 AM  |  Printer friendly version | E-mail to a friend | By Darrell Blackwelder

For the Salisbury Post

Tomatoes are a major home garden vegetable that, unfortunately, can be difficult to grow. Below are questions from both novice and experienced home vegetable growers posed over the past few weeks.

Q: I have beautiful tomato plants and tomatoes, but they are not ripening. Is there something wrong with my plants?

A: No not really, you need to be patient. Tomatoes need heat to ripen and even though we've had plenty of heat in the day, the night temperatures have been fairly cool and they aren't ripening quickly. They will eventually ripen.

Q: My tomato plants keep growing and growing. What can I do to keep them at a height I can pick?

A: You have an indeterminate tomato cultivar. It will grow all summer as long as it gets plenty of water and fertilizer. You can prune it back to keep it from getting too high to pick, but you may be removing some of your blooms/fruit. Consider a determinant cultivar that grows to about 3 feet and stops growing.

Q: Some of the fruit on my tomato plants are ugly and misshapened. What causes this?

A: Poor pollination is generally the cause for cat-facing. Cat facing is usually caused by temperature extremes. It does not affect the taste of the tomato.

Q: There are beetles on my tomato plants eating the leaves. They are brown and look very similar to lady beetles. What are these insects and how do I control them?

A: These insects are most likely bean beetles. They feed on a variety of vegetable crops including tomatoes. Sevin dust or liquid will control beetles.

Q: My tomatoes have curled leaves. What is the problem?

A: Some tomato varieties have curled leaves as part of their growth habit. This is normal and the tomato plants will bear edible fruit.

Q: The leaves on my tomato plants (plants were brought into the office) have spots on the leaves, turning yellow and are dying. The leaves start at the bottom and work their way up to the top of the plant. What is the problem and how can I control it?

A: The tomato is infested with early blight, a very common fungal disease on tomatoes. If practical fungicidal sprays such as manzate or zineb will slow the disease. Sulfur and copper sprays may also help, however, costs and time associated with controlling the diseases on a few plants may be prohibitive.

Darrell Blackwelder is an agricultural agent in charge of horticulture with the North Carolina Cooperative Extension Service in Rowan County. Contact him at 704-216-8970 or darrell_blackwelder@ncsu.edu.

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