For Release On Or After 06/04/10

If you planted your tomatoes at the right time – from March to mid-April – you should be harvesting delicious, vine-ripened tomatoes by now. If you didn’t plant tomatoes for yourself, check your local farmers markets. They’re well-supplied with all types of locally grown tomatoes that were allowed to ripen or nearly ripen on the vine for excellent flavor.

As soon as hot weather arrives in May, tomatoes seem to have more than their share of problems. Although most of us still end up getting a decent crop, some problems are especially tragic.

Bacterial wilt is certainly one of these. Once the bacteria move into the tomato plant from the soil or by insects, they multiply rapidly, moving into the vascular system and clogging it. This prevents water from moving from the roots into the upper plant. The tomato plant suddenly wilts, and watering will not revive it.

Bacterial wilt can be diagnosed with a simple test. Remove the wilted plant from the soil and rinse the roots and lower stem. Then, cut a section about 4 inches long from the lowest part of the stem just above the roots. Have a jar of water ready so that the stem section can be suspended in the water, bottom end down, using a paper clip. Now, watch for wispy, cloudy ooze at the bottom end of the stem. If it occurs, you’re seeing bacterial streaming. Although this bacterial ooze is almost transparent, you can see it releasing from the base of the stem.

If you have bacterial wilt, you can’t do much except remove and dispose of affected plants. But don’t put them in your compost pile because the bacteria will continue living there to contaminate the soil where you apply the compost later. And don’t plant your tomatoes in the same location in the future. Even if you put them in containers over the infected soil, the roots could grow through the bottom of the container and contract the disease. And don’t reuse stakes or ties from infected plants.

Another tomato malady – blossom end rot – is a physiological disease. It’s caused by a calcium imbalance in the fruit, not by a pathogenic organism. Affected tomatoes have a round, dark brown, dry, sunken area at the bottom of right around where the blossom fell off.

Several factors may cause blossom end rot. Wide fluctuations in soil moisture can lead to this problem. Plants in containers are especially vulnerable because the soil in the pots dries out so quickly. Excessive phosphorous in the soil can interfere with calcium uptake, so be cautious about using fertilizers high in phosphorus – the middle number in the analysis. Although a calcium deficiency in the soil will cause blossom end rot, have your soil tested before adding any calcium.

To deal with a current problem, treat plants with a product labeled to control blossom end rot in tomatoes. These products, available at local nurseries and garden centers, contain calcium in a rapidly available form and are sprayed onto the plants.

Tomatoes may turn soft and mushy because of a small wound caused by splitting at the top or holes from tomato fruit worms. Once the tomato skin is broken, microorganisms get into the flesh and cause the rot.

Inspect your tomatoes frequently. If you find any that show a crack or hole, harvest, rinse and dry them and let them ripen indoors on the kitchen counter. Many gardeners harvest tomatoes in the pink stage and let them ripen indoors out of harm’s way. If you do this, light is not important to the process – there’s no need to put them in a window.

A dropped flower is like a broken promise. Everyone hates to see flowers drop, but it’s common with tomatoes at this time. The main crop is already set on your plants. Once a plant begins developing all the fruit it can handle, it will tend to drop most or all of the flowers it continues to produce. You can do nothing about this, and there’s no need for concern.

Another reason for flower drop is that high temperatures interfere with pollination. Without good pollination, either the flower will not set fruit and drop off, or the fruit that is formed will be irregularly shaped.

If you planted heat-tolerant varieties, such as Solar Set, Sunleaper or Heatwave, you may find they are more reliable at producing fruit through the summer. In addition, small-fruited cherry tomatoes and plum tomatoes generally remain productive despite the heat.

We tend to harvest our best, highest-quality tomatoes in late May and June. By mid- to late summer, intense heat and growing pest and disease populations – such as caterpillars, birds, stink bugs and fruit rot – take a heavy toll. Keep your plants properly watered and mulched and control pests when needed, and you’ll ensure the best harvest you can get.

We generally don’t maintain tomato plants in late summer after production stops or diminishes and the plants look bedraggled. Typically, we pull out our spring and early-summer plants and set out a new crop of young transplants in August for a fall crop. So, if you weren’t happy with this go-round, you’ll have another chance in a few months.