By Stephanie Butcher, Coweta County Extension Service
Question: Last year my tomato plants were beautiful, but I got very few tomatoes. I want to have a better crop this year. Can you tell me what I did wrong so that I can fix it this year?
Agent: If your tomato plants grew large and had dark green, healthy foliage, then chances are they received too much nitrogen. This is actually a fairly common problem. Too much nitrogen can cause vigorous vegetative shoot growth but few blooms or fruit. This is one of the reasons why soil tests are important prior to planting.
Tomatoes are medium feeders and will require fertilizer beyond the initial starter solution. In the absence of a soil test, incorporate 1.5 pounds of 10-10-10 fertilizer for 100 square feet of bed prior to planting. Use a complete fertilizer that contains minor nutrients. After the first tomatoes form on the vine and are about the size of a quarter, sidedress them with 10-10-10 at the rate of 1 pound per 100 square feet of bed. Repeat every three to four weeks until harvest is completed.
You may see different problems this growing season from what you experienced last year. In very wet growing seasons, like the one we are experiencing now, it is not uncommon to see some nitrogen deficiency in tomato plants, which is why soil testing is so important.
Other problems you may see include fruit cracking, blossom-end rot, catfacing, or bacterial wilt. This isn’t an all-inclusive list of course, but these are some of the most common things that you can look for. Look for resistant varieties to help avoid some of these issues.
Fruit Cracking is due to rapid growth after periods of slow growth. Excessive rain, rain after drought and heavy fertilization can cause this problem. Harvest your tomatoes after they begin to turn red but before they crack. Look for cracking resistant varieties.
Blossom-end Rot (BER) appears as a dry leathery spot on the blossom end of tomatoes. The spot is usually on the blossom end, is tough and leathery and slightly sunken. It is caused by lack of calcium. Inadequate water supply, low pH or low soil calcium levels can cause this problem.
Once a plant has BER, it is hard to control. Calcium is best taken up by the roots so sprays are not very effective, but plants will often grow out of the problem as growing conditions improve.
Catfacing is caused by cool temperatures at time of pollination. The fruit is deformed with ‘zippers’ on the skin. The fruit can have lobes, tear drops or several blossom scars. Plant resistant varieties, plant later, or use row covers to increase the temperature on cool days and nights. The large beefsteak varieties appear to be more susceptible. The fruit is still edible.
Bacterial Wilt causes a rapid wilting and death of the plant. The plant dies so quickly it does not have time to yellow. To identify bacterial wilt, cut through the stem. Bacterial wilt browns the pith or middle of the stem. Cut a short section of the stem and suspend it in a clear glass of water. You can often see a milky ooze streaming out of the bottom of the cut stem. There are no controls or resistant varieties for bacterial wilt. Carefully dig out infected plants and soil and discard.
For more information about common tomato problems, call the Coweta County Extension office at 770-254-2620 and ask for the publication, “Georgia Home Grown Tomatoes”.
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Photo credit: Chatham County Cooperative Extension – North Carolina State University