This article was written with the assistance of Mr. Chase Powell. Chase is interning at the Colquitt County Extension office this summer.
It has officially circled to the time of year that Blossom-end Rot is starting to become an issue. Blossom-end rot, also known as (BER), is common among peppers and tomatoes. This occurrence can also happen in eggplant and the cucurbit family. Many growers associate this with a disease, but it is not. Calcium deficiency is what causes this disorder.
Calcium has numerous functions in plants such as helping extend primary root systems, cation and anion balance within the plant, and providing stability for the cell membrane/wall. Calcium is taken up by the plant and moves throughout the plant with water. Leaves will also contribute to the problem, which can be caused by long, hot, and dry weather. During these times, it is very easy to lose calcium through the leaves in a process known as transpiration. Keeping the nutrient is crucial. For example, if the nutrient is deficient during the early developing stages of the fruit, then the cell membrane will collapse. The first visible sign that BER is affecting the plant would be a small water-soaked area at the blossom end of the fruit, then it will progress into a dark and sunken spot on the bottom of the fruit as it matures. The process will then grow into having an almost leathery bottom. This will eventually open a gateway for other rots to invade the fruit.
Fruit disorders can easily be confused with Blossom-end rot. Although there are only a few, it can be puzzling. Buckeye rot is caused by Phytophthora and will closely resemble the blossom-end rot in color. Sunscald will parallel this process as well, but sunscald will appear on the side walls of peppers. In addition, it will also appear pale in color. Anthracnose is likewise commonly confused with BER, but anthracnose will grow lesions on the sidewalls of the fruit. In contrast to these examples, blossom-end rot will only form on the bottom of the fruit. It will also never start at the stem end.
To help avoid blossom end rot, a few methods have been found to work:
For these reasons, BER is better prevented than cured. Prevent it with these tips.
- Before planting, soil sample and lime to bring the pH up to 6.0. Add lime one to three months before planting.
- Add gypsum (calcium sulfate – one cup per plant or one to two pounds per 100 square feet) to the soil before planting. Gypsum works more quickly than lime to supply calcium to the plant. To find gypsum, call farm supply dealers or feed and seed and hardware stores.
- Plant in soils that are well-drained and tilled at least eight to twelve inches deep.
- Water established plants with three-quarter inches of water twice a week. Do not waterlog plants or let them suffer from drought, especially early in the development of the tomato fruits. Water plants deeply and then let the soil dry slightly before watering again.
- Mulch around plants to keep the soil from drying out. Pull mulch slightly away from the main stem of the plant.
- Side dress tomatoes once every five weeks if necessary. Fertilizers can supply nitrogen in two forms – ammonium and nitrate. Use calcium nitrate, 5-10-15, 10-10-10, or similar fertilizers and look for fertilizers that have a higher percentage of nitrate nitrogen and lower levels of ammonium nitrogen. Read the fertilizer label to find this information. This is especially important when the fruit is small. Try to wait until tomatoes are the size of a quarter before you side dress.
- Be careful when hoeing or cultivating. Damaged roots will not take up calcium well. Do not heavily prune tomatoes. This can make them more susceptible to BER.
- Once you have BER there is nothing you can do for affected fruits. Use these practices to prevent BER in new fruits. Often the first tomatoes are affected and later fruits are okay. In other words – the condition may get better as the plant matures.
- There are some calcium-containing sprays for BER. Sprays applied to the leaves do not control BER well because calcium usually enters the plant through the roots and should be applied to the soil. Calcium is not moved around in the plant well and may not make it into the fruit if we apply it to the leaves. If you want to treat affected plants with calcium, pour solutions of calcium chloride or the Blossom End Rot sprays around the tomato plant’s roots. The plant can take up calcium more readily this way.
- Another option is to sprinkle one-half cup of gypsum around the plant and water it in. Expect slower results using gypsum as compared to treating the soil with calcium chloride. If you cannot find gypsum – you can use lime but expect even slower results.
When dealing with Blossom-end rot, both nutrient and environmental factors should be considered. Being able to correctly identify the problem can save massive amounts of money and time. Additional examinations of soil tests and leaf analysis can help determine how far the grower will have to go to resolve the problem. Knowing basic fruit development, plant growth, and Calcium movement in plants will help diagnose and correct the effects of BER.
If you have questions please contact the Colquitt County Extension office at 229-616-7455..