Several weeks ago I went to pick the first ripe tomato my garden produced this year. I watched it change to a deep red-orange over many days, waiting with impatience for it to ripen perfectly before I would pick it. Finally the day came. I plucked the plump tomato off the vine and turned it over in my hand, only to find that the bottom of it was all black and rotten. What a disappointment!
A quick look under the other tomatoes on the same plant showed that several of them all suffered from the same malady: blossom-end rot.
Many gardeners have encountered tomato blossom-end rot for the first time this year. It often hits after a hot dry spell, which we certainly had throughout July. Tomatoes are most often the victims but it can also affect eggplants and sweet peppers.
There is no cure for blossom-end rot once it starts, but it can be prevented. The reason for the rot is that the plant isn’t getting enough calcium from the soil. When the tomatoes’ cells don’t get the calcium they need, they collapse and become discolored. When it doesn’t rain, the plant can’t take up calcium even if it is available. Obviously, one way to prevent blossom-end rot is to give tomato plants consistent watering.
There are a few other things you can do as well. Avoid high-nitrogen fertilizers which tend to block the plants’ uptake of calcium. Instead, fertilize with compost, rotted manure or a blended organic fertilizer that contains a broad range of trace nutrients.
Mulch around the tomato plants to conserve what moisture there is in the soil. High humidity interrupts nutrient transport to the fruit. Make sure there is plenty of space between plants and avoid wetting the leaves when watering.
Damaged feeder roots cannot take up calcium properly. Handle transplants carefully when setting them in the ground and be careful not to cultivate too closely to the plants once they are established.
There are a few ways to provide plants with extra calcium. When planting, sprinkle powdered milk into the planting hole. You can also mix powdered milk into the water you use to water them. Save your eggshells over the winter and crush them to mix into the soil around the root zone of the plants when you plant next spring.
The top part of a tomato with blossom-end rot is safe to eat, but if you notice the rot on a tomato that hasn’t yet ripened, throw it in the compost and allow the plant to put its energy into ripening the unaffected tomatoes.
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