Most tomato gardeners are all too familiar with blossom end rot. There is nothing more frustrating than reaching for that juicy, red tomato only to find the bottom rotting. It is a very common disease that affects both home gardeners and commercial growers. Blossom end rot is caused by a lack of calcium in the plant that is usually the result of fluctuating water supply.
Rotten tomatoes
The rot begins with a water soaked spot at the bottom, or blossom end, of green or ripe tomatoes. The spot turns brown or black, becomes dry, leathery, and larger. The disease often starts when tomatoes start to put on some quick growth and are suddenly hit by a hot, dry spell. The problem is brought on by moisture stress. Often, the disease is prevalent early in the season, but will diminish as the season progresses.
Prevention of blossom end rot
Prevention is the best cure. You need to try and keep the water supply even during the growing season. Tomatoes don’t want to dry out; they need watered before they wilt. Mulch is a big help. It conserves soil moisture and keeps weeds down.
It is important not to cultivate the soil more than an inch deep to control weeds around the plants. Cultivating deeper can damage valuable feeder roots and encourage rot.
Tomatoes planted early in the season in cold soil seem more susceptible to blossom end rot. First fruits may be affected with the severity of the problem subsiding as the soil warms. Consequently, waiting to plant in warmer soil helps.
Treatment of blossom end rot
I repeat; prevention is the best cure. However, if you are facing a blossom end rot crisis, some things you can try to control the problem on tomato plants are:
Calcium chloride- Calcium chloride is sold at hardware stores as ice-melt salt. If you can find it during growing season, you can try mixing one tablespoon per gallon of water and spraying the plant foliage two to three times a week.
Milk- Pour three cups of whole milk near the base of the plant once or twice a week. Rinse any milk spots off the leaves.
Lime- Test the pH of your soil. The pH should be maintained at 6.5. If needed, add lime to supply calcium to the soil.
Once you find the spot there is no way to save the fruit. Although it is ugly, it is safe to eat fresh. Just cut away the bad part and enjoy the rest.
Sources:
http://vegetablemdonline.ppath.cornell.edu/