Blossom-End Rot

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Summer is here and I am sure that all of your gardens are looking green, lush and beautiful. Many of your early fruiting tomatoes and cucumbers are ready to pick and have hopefully avoided the early and detrimental insect and disease pressures. Every thing is probably looking great except for the reoccurring problem of Blossom-End Rot.

Blossom-End Rot is a physiological disorder that causes the decay of the flower end of fruits on tomatoes, cucumbers, squash and many other garden crops. This disease is a true physiological problem, meaning that it is not cause by a living disease, but rather a lack of access to the nutrients that are required for healthy growth and development. In the case of Blossom-End Rot, it is a lack of calcium that creates this dead spot on the fruit. Starting with a spot the size of a dime, Blossom-End Rot will progress to a large soggy, dead spot that makes every fruit inedible. This problem will continue to affect the fruits until the plant is able to gain access to calcium in quantities sufficient for healthy growth. It has also been shown that irregular watering will also encourage the development of this problem.

Since Blossom-End Rot is caused by a lack of calcium, the cure is usually simple… add more calcium. While this will often work, fertilizers with calcium are readily available in the form of calcium nitrate or calcium chloride, the best way to cure this problem is making sure that the calcium already present in the soil is made available to the plant. In Randolph County, many of our soils are composed of heavy clays that are predominately acidic with a pH less than 7.0. In acidic soils, calcium tends to get locked into the clay due to the strong magnetic attraction that is present. It has been found that increasing the pH of the soil will allow that calcium to be released from the clay, making it available to the surrounding plants. Increasing the pH of your soil is easy with the use of lime in either a liquid or a granular form. Granular lime should be mixed in with the soil as much as possible without damaging the roots of the plants. Liquid formulations should be used in accordance with the label.

Other control methods for Blossom-End Rot are mainly related to irrigation and proper watering techniques. Tomatoes in particular are extremely sensitive to rapid changes in the environment. These plants enjoy being water on a regular basis and will show weird growth and development patterns when drought or flood conditions occur. Tomatoes also do not enjoy having their leaves wet. Overhead irrigation tends to have unintended consequences such as increased fungal sensitivity and fruit drop. Keeping the moisture available to your plants will increase their ability to fight disease and create more delicious fruits. The use of mulch and drip irrigation will ensure that your garden is receiving the proper amount of water and give it the ability to keep that water near the roots where it can be utilized.

Proper plant nutrition is key for a healthy garden. The Cooperative Extension is here to help with your soil nutrient testing needs. A soil test is a simple and affordable way to keep your plants healthy and happy. It also avoids the wasteful application of unnecessary fertilizer.

Here at the Randolph County Cooperative Extension, we strive to help and educate the public in whatever way we can. If you have any questions about gardening or crop production, please feel free to contact us at the Randolph County Cooperative Extension office by phone at (336) 318-6000 or in person at 112 W. Walker Ave. here in Asheboro.