Washington State University

Gardening in Washington State

Blossom-end Rot of Tomato and Pepper

Blossom-end rot is a plant disorder that appears as a water-soaked, light brown spot on the blossom end of the fruit. As the fruit matures, the spot becomes sunken, leathery, and brown to black. Opportunistic pathogens can infect this spot leading to fruit rot. Blossom-end rot is associated with a lack of sufficient calcium in developing fruit. Often the disorder is only noticeable on the earliest maturing fruit of the season. Blossom-end rot may be traced to excessive soil moisture, drought stress, or excessive fertilization. Prior to planting next year’s crop, send a soil sample in for testing. Your county extension agent can recommend soil-testing laboratories in your area. If your soil is low in calcium, use lime or dolomite lime at least 2–4 months before planting. Plant in well-drained soils and water consistently. Mulching plants may be helpful. Fertilize moderately to avoid buildup of salts in the soil and to prevent excessive growth.

Blossom end rot on tomato Blossom end rot on pepper
Blossom end rot of tomato (left) and pepper (right)

Crops affected: Tomato, pepper, eggplant, and various cucurbits.

For more information on tomato blossom-end rot, see Growing Tomatoes in Home Gardens FS145E as well as WSU Hortsense

Submitted by: Michael Bush, June 8, 2015


2 comments on “Blossom-end Rot of Tomato and Pepper”

  1. Curtis C said on August 24, 2015:

    I have been growing tomatoes for years now. I still hate to see blossom end rot . I have used garden Gypsum to combat this problems and also crushed Egg shells. These two items will add the necessary calcium needed.

    • Chalker-Scott, Linda K said on August 24, 2015:

      Neither gypsum nor eggshells are science-based methods of treating blossom end rot, so they are not recommended by WSU.

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