Released July 10, 2009
SEARCY, Ark. - Calcium is great for strong bones, but it’s also great for strong tomatoes, said Sherri Sanders, White County extension agent for the University of Arkansas Division of Agriculture.
"Tomato season is in full swing and like most years, blossom-end rot of tomatoes and other vegetables is a problem that occurs from time to time," she said. "The cause of blossom-end rot is a calcium deficiency in the fruit."
There are several factors contributing to this problem including root pruning or damage, low moisture levels, and of course, lack of calcium in the soil.
"Anything that interferes with calcium uptake by the root system of the plant can cause blossom-end rot," Sanders said.
Symptoms of blossom-end rot are light tan lesions turning to dark brown sunken areas, usually at the end of the fruit. Some lesions may occur on the side of the fruit. The lesions are usually large and become more sunken and leathery accompanied by dry rot. A black mold may grow on the surface of the lesion.
Several steps can be taken to prevent or control blossom-end rot. Soils should be limed to a pH of 6-7. Timely irrigation to provide a constant moisture supply goes hand in hand with the lime, which provides calcium to the plant.
"Stopping blossom-end rot once it has started is more difficult than preventing it," she said.
If the problem is lack of moisture, this can be corrected by simply irrigating. If the problem is a low pH or lack of calcium in the soil, the problem may be more difficult to control. Because calcium is immobile in the plant, calcium sprays may not be effective. Applications of calcium materials to the soil, either as a side dressing or through drip irrigation tubing, would probably work better. Materials to use would include calcium chloride or calcium nitrate.
To see what blossom end rot looks like click http://www.aragriculture.org/diseases/image_library/tomato_vegetables/tomato/blossom_end_rot.htm.
For more information on managing tomatoes, download our online publications "Tomato Diseases in Arkansas," MP430, http://www.uaex.edu/Other_Areas/publications/PDF/mp430.pdf, and "Tomatoes: Home Gardening Series, " publication FSA6017, http://www.uaex.edu/Other_Areas/publications/PDF/FSA-6017.pdf.
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http://www.uaex.edu/news/july2009/0710blossomendrot.htm
Contact: Elizabeth Fortune, (501) 671-2120, efortune@uaex.edu
