AUBURN, Ala. – Tomato plants are some of the most popular things grown in gardens. There are many varieties on the market and each one offers something different. One problem that tomato growers face is blossom-end rot (BER). An Extension professional discusses the causes of BER and some control methods.
Chris Becker, an Alabama Extension coordinator in Limestone County, said blossom-end rot is a disease that affects the fruit of a plant.
“Blossom-end rot is an abiotic disease, caused by nonliving factors,” Becker said. “It starts out as a brown, dime-sized lesion near the blossom-end and increases in diameter as the condition worsens.”
Causes of Blossom-End Rot
A calcium deficiency within the plant causes BER. A change in a plants water supply is usually the cause.
Becker said even a slight change can affect the plant.
“Calcium is not a highly mobile element in a plant. Because of this, even brief changes in the water supply can cause BER,” Becker said.
Drought stressed soil and roots damaged from excessive or improper cultivation can restrict a plants water intake. This prevents the plant from getting the calcium it need for healthy growth. Plants growing in highly acidic soil or in areas that have too much water can also have calcium deficiency and develop BER.
Controlling Blossom-End Rot
According to Becker, growers should remove infected fruits if they experience severe problems with BER.
“Once a fruit develops blossom-end rot, it will not regrow or repair the infected area,” Becker said. “In fact, the damaged area could serve as an entry point for disease-causing bacteria or fungi.”
It is generally easier to prevent blossom-end rot rather than wait and treat the problem. The following are a few tips on controlling blossom-end rot.
During fruiting, tomato plants need about 1.5 inches of water each week. It is important that plants get an adequate amount of water. Extreme changes in soil moisture can increase the chances of a plant getting BER. Use mulches like pine straw, composted sawdust and also newspapers to help conserve moisture.
Becker said if plants develop BER, growers can apply a calcium solution.
“Drench the root zone with the solution at the rate of four level tablespoons of calcium nitrate or calcium chloride per gallon of water,” Becker said. “If day temperatures are greater than 85 to 90 degrees, do not use calcium chloride because foliage burn can occur. Calcium nitrate is the better option for hot days”
Plant Different Varieties
Some tomato varieties tend to be more sensitive to the conditions that cause BER. Becker suggests growing several varieties of tomatoes and keep notes on their performance.
Perform a Soil Test
A soil’s pH level should be kept between 6.0 and 6.5. Becker said perform a soil test two to four months before planting.
“A soil test will show what levels need to be adjusted. Apply the recommended rate of lime, using dolomitic or high-calcium limestone,” Becker said. “Also, apply fertilizer as recommended, because applying too much fertilizer can induce BER.”
Collecting a soil sample is an easy procedure. For information on how to collect and send a soil sample for testing, visit the Soil, Forage & Water Testing Laboratory’s website. The fee for testing a is $7 per sample. Soil test boxes as well as sample forms are available at any county Extension office.
For more information on blossom-end rot, visit Alabama Extension online or contact your county Extension office. Alabama Extension has the publication Backyard Tomato Production that provides information on every step of growing tomatoes.
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