I’ve received several questions from gardeners expressing concern over their home grown tomatoes that develop sunken brown spots or black rot on their bottoms which totally ruins the fruit.
The probable cause is a disease called Blossom End Rot which affects tomatoes, peppers, squash, and watermelons.
Cause and Symptoms of Blossom End Rot on Tomatoes
While there’s no way to save the individual tomatoes or other fruits that show signs of blossom end rot, overall it’s not a major concern for the organic gardener and the disease doesn’t spread or actually affect the plant itself. You’ll see more blossom end rot occurring on tomatoes early in the season with it appearing less frequently as the summer goes on.
Blossom End Rot is caused by a calcium deficiency and there are organic products on the market that can be applied to vegetable plants to help reduce the incidence of rot striking tomatoes and other susceptible fruits. Because the problem is usually temporary and will resolve itself I don’t recommend treating the plants with any type of spray to combat blossom end rot.
Often the problem has more to do with the moisture levels in the garden to regulate the delivery of nutrients than the amount of calcium available in the soil, and tomato rot will be more noticeable after periods of uneven precipitation such as when drought conditions are followed by periods of heavy rain.
Organic Control and Prevention of Blossom End Rot
So a better way to combat blossom end rot is to ensure that your growing beds contain plenty of organic matter to help maintain even moisture levels and by watering your tomatoes as needed during periods of low precipitation.
Some gardeners claim that planting tomatoes out in the garden before the soil has thoroughly warmed up can promote the occurrence of blossom end rot. Don’t plant those heirloom tomatoes, peppers, squash, eggplants, and watermelons out into the garden until the soil has had a chance to fully warm up.
Other precautions include avoiding cultivating too closely to the plants which may encourage blossom end rot by destroying the tiny feeder roots that grow close to the soil surface and supply moisture and nutrients to the plants.
Mulching the soil after temperatures rise will help to conserve the amount of moisture that is retained in the soil and prevent or lessen the amount of blossom end rot on your tomatoes and other vegetables.
For gardeners seeking a natural spray to control blossom end rot on tomatoes, peppers, and melons, “Garden’s Alive” sells a product called Rot-StopT Spray that can be applied to your plants once a week to supplement calcium reserves and prevent rotting.
So don’t panic or be overly concerned if you see your tomatoes suffering with signs of blossom end rot early in the season. Simply remove the affected fruits that display the sunken rotten bottoms, irrigate to maintain even moisture, and be patient… that’s usually the most effective organic control to handle this common problem in the vegetable garden.
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