Gardening Tips: Blossom End Rot on Tomatoes
One of the most common problems found in vegetable gardens across the county is something called blossom end rot. Nearly everyone who has attempted to grow tomatoes in their garden has encountered this problem. It can be a confusing problem for a homeowner to solve, as it is not caused by insects or disease. What does cause this all-to-common problem, and what can be done about it?
Blossom end rot is a physiological disorder caused by a deficiency of calcium in the tomato fruit. This deficiency results in the decay of the blossom end of the tomato. The fruit turns brown and leathery in areas ranging from the size of a dime to a half dollar. The symptoms usually appear to be worse on the earliest fruit, but may persist throughout the season in some cases.
Because the primary cause of this problem is a lack of calcium, the simple solution is to ensure that there is a sufficient amount of calcium available to the plant. This can be done in a number of ways. First, it is important to know where the plant gets calcium from. The plant takes up calcium, along with the other essential nutrients, from the soil. Therefore, it is necessary for the soil to have an appropriate amount of calcium present, and a pH of 6.5 to 7.0 to allow this calcium to be available to the plant. The only way to know for sure if this is the case is to do a soil test. This can be done through the Cooperative Extension Service. A soil test will tell you, among other things, the pH of your soil and how much calcium is present, and whether you need to add fertilizer or lime.
Lime will do two things. First, it will raise the pH of your soil, which is important because most North Carolina soils are naturally below the necessary 6.5-7.0 pH range. Second, it will provide calcium in the soil, as lime contains calcium. Mix the appropriate amount of lime recommended by the soil test into the top 4-6 inches of soil prior to planting. This should get your tomato plants off to a good start, but watering is very important as well. Tomato plants need at least 1 inch of water per week from rainfall or a hose, and may need as much as 1.5 inches when fruiting. Very dry conditions, or shifts in extremes between very wet and very dry soil can also cause blossom end rot to develop. Using bark or straw mulch and compost will help to maintain a good amount of moisture in the soil.
There are also a number of products available to provide a supplemental amount of calcium, such as Tomato-Saver and Blossom End Rot Preventer. These are liquid sprays which can be applied to the leaves of the tomato plant during the flowering stage and weekly thereafter. Rinsed egg shells and Epsom salt are also good sources of supplemental calcium.
Be careful not to over fertilize. A large amount of fertilizer applied at one time, or several applications of a high N fertilizer can also trigger blossom end rot. Again, utilizing a soil test will ensure you are applying the right amount of fertilizer.
Be sure to support the Roanoke Valley Farmers Market on rt. 158 in Roanoke Rapids on Saturdays, 8-3, and in Halifax on Wednesdays 8-5. Both markets feature a wide variety of fresh fruits and vegetables, live plants, baked goods, crafts, jewelry, clothing and more. New vendors of all types are always welcome, contact Matt Stevens for more information.
Matthew Stevens is the horticulture extension agent for HalifaxCounty Cooperative Extension. If you have any questions about this article or other aspects of your home gardening, please contact Matthew at 583-5161 or .