Selecting, growing and harvesting tomatoes can be such a fun and rewarding summertime experience. What self-respecting Southerner doesn’t love a tomato sandwich supper in the summer? In the last posts we discussed planting tomatoes.
Here are a few tips on selecting and harvesting and pest control.
- For best quality, harvest tomatoes when they are fully ripened on the vine. If harvested before they are ripe, but after they reach the mature green stage, tomatoes can be allowed to ripen in the home.
- Place unripe mature green or pink fruit in a room with a temperature of around 70 degrees F. Fruit should be well-ventilated and not jammed together.
- Fully ripened fruit may be placed in the refrigerator to prolong keeping, but never put unripened tomatoes in the refrigerator. Tomatoes can last several weeks under refrigeration.
Tomato Variety Selection
- When it comes to tomato varieties, the sky is the limit. They come in a large assortment of shapes, sizes and colors. While it is fun to experiment with the new and exotic tomato varieties, this publication will focus on tried and true varieties for our state. Regardless of which plants you choose, you will need to be familiar with some terminology to make the right choices.
To be Determinate or not Determinate ( Indeterminate)
One of the most important factors in deciding what kind of tomato to grow is deciding the end use of the tomato first. Canning? Eating fresh? Making sauce?
For canning, determinate tomato varieties are best. They grow in a more compact bush form and produce most of their crop at one time. You can harvest all of the fruit in two to five pickings and then pull up the plants. Determinate varieties often produce an early crop, so you will want to plant successive plantings in order to harvest tomatoes over an extended period of time with this type of tomato.
Indeterminate varieties set fruit clusters along a vine stem that continues to grow all season. They will continue to produce fruit, if harvested, throughout the season until first frost. Bush varieties do best when staked or grown in cages, but vine types must be given support.
Because tomatoes are susceptible to diseases, viruses and insects, some varieties have been bred or hybridized to be resistant to certain pests. Resistance to these pests is usually listed on the plant label.
Disease and Insects
Although tomatoes are fairly tolerant of insect damage, they will occasionally have trouble from some common garden pests. Whiteflies, hornworms, aphids, leafminers, stinkbugs, loopers, cutworms and mole crickets (south Georgia) have been known to cause problems on tomatoes.
Insecticidal soap and Bt (Bacillus turingiensis) are used by many organic gardeners with fair success. Repeated applications and scouting for pests frequently are necessary for continued control. A general purpose garden insecticide applied according to label directions will control most of these pests. Use care, however, when spraying because these pesticides will also kill many of the beneficial insects that are protecting your garden naturally.
Diseases and viruses on tomatoes can be a real problem for the home gardener. For detailed information on tomato diseases, please refer to a separate publication available from your local county extension office. Cultural practices discussed earlier in this publication, and improved variety selection, will go a long way in preventing disease problems. It makes more sense to maintain a healthy plant and prevent disease problems, than to rely on spraying multiple chemicals for control.
Early blight on tomato plant leaves. Blossom-end rot on tomatoes.
Blossom-end rot can be a serious problem with tomatoes. The main symptom is a dark, sunken water-soaked area at the blossom end of the fruit. This physiological disorder is associated with a low concentration of calcium in the fruit. Blossom-end rot is also induced more often when there is drought stress followed by excessive soil moisture; these fluctuations reduce uptake and movement of available calcium.
To manage blossom-end rot:
Maintain the soil pH between 6.2 to 6.8 and supply adequate levels of calcium through applications of dolimitic limestone or gypsum.
Avoid drought stress and extreme moisture fluctuations by using mulch and deep, timely irrigation once or twice a week.
Avoid overfertilizing plants with high ammoniacal nitrogen fertilizers. Excessive nitrogen can depress the uptake of calcium.
Foliar applications of calcium with products such as Blossom End Rot Stop, are only short term fixes and often work poorly because of poor absorption and movement to the fruit area where it is needed.
For more information on growing the South’s favorite summer veggie, visit UGA Extension’s website at
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