Blossom End Rot

If you grow tomatoes, you are familiar with Blossom end rot. This disease can cause severe loss in both garden and home tomatoes if precautionary measures are not taken. Symptoms can happen at any stage in the development of the fruit. Most often however, it can be seen when the fruit is one-third to one-half of its full size. As implied by the name, symptoms will only occur at the blossom end of the tomato. First you will see a small, water soaked spot which will eventually grow and darken rapidly. This spot can grow until it covers as much as one-third to one-half of the full fruit. However, the spot can stay small and superficial. Large areas will quickly dry out and become flattened, black and leathery.

The disease doesn’t spread from plant to plant in an area, nor from fruit to fruit in transit. Therefore, since to the physiological nature fungicides and insecticides are useless. The occurrence of the disease is reliant on environmental factors. Factors that influence the uptake of water and calcium through the plant have an effect on the incidence and severity of the disease. Blossom End Rot is most common when there is rapid growing and then a sudden period of drought. What happens when the roots fail to obtain sufficient water and calcium that need to be transported up to the fruits- they become rotted on the ends. Another common predisposing factor is cultivation too close to the plant; this practice destroys valuable roots, which take up water and minerals. Tomatoes planted in cold, heavy soils often have poor root systems. Since they are unable to supply the necessary amounts of water and nutrients to plants during times of stress, blossom end rot may happen. Soils that contain excessive amounts of soluble salts may lead tomatoes to the disease, for the availability of calcium to the plants decreases rapidly as total salts in the soil increase.


We are starting to notice Blossom End Rot at the greenhouse in beds. Here is an organic way to control the disease. Use Epsom Salt!

To prevent blossom end rot, work Epsom Salt into the garden soil before planting tomatoes. Apply one pound of Epsom Salt to the standard sized raised bed garden (4 x 6-8’) or one cup of Epsom Salt per container that tomatoes will be grown in and work into the soil. The Epsom Salt will then be a readily available source of calcium and magnesium for the tomato plant.
Epsom Salt also promotes root growth and development for all garden vegetables and flowers and should be worked into the soil along with organic matter at the beginning of spring. A side dressing of Epsom Salt or watering gardening vegetables with a mixture of ½ cup of Epsom Salt dissolved in one gallon of water a couple of times during the growing season will keep plants healthy and growing vigorously. When applying dry Epsom Salt as a side dressing, be careful not to allow the Epsom Salt to touch any part of the plant.

Thank you to Twin Oaks Nursery and Cornell University for the original information! You can click on their names to read more!

Posted in 2016 Project Bloom, Garden Chores and Tips, Gardening Tips, Project Bloom and tagged , , , , , , , , , , .