Blossom-End Rot

This condition is caused by a calcium deficiency--not a disease--brought about by extremely wet or dry soil. When rain or irrigation follows a dry spell, calcium cannot be taken up fast enough by the roots to keep up with the rapid fruit growth. Even though there may be plenty of calcium in the plant tissue, it cannot be delivered to newly developing plant tissue. Blossom-end rot also occurs if the delicate feeder roots are damaged during transplanting or when cultivating deeply near the plants.

Control: A calcium nitrate or calcium chloride solution can be applied as a drench around the base of the plant or as a spray to the entire plant as soon as the rot is detected or earlier. Maintain a pH of 6.0 to 6.5 and an adequate calcium level by liming or applying gypsum according to the results of a soil test. Keep moisture levels fairly uniform by maintaining a one- to two-inch layer of mulch around the base of the plants. Finally, avoid overfertilizing because an excessive accumulation of salts will inhibit the uptake of calcium.