Blosson end rot?
Hi- this is a common nutritional disorder of tomatoes caused by a shortage of calcium in developing fruits. Fruits may experience a calcium shortage if there is a calcium deficiency in the soil or plants are subject to extreme water fluctuations. Factors that encourage blossom-end rot include: low soil pH, low levels of calcium, inconsistent watering, shallow watering, droughty conditions, and excessive use of nitrogen fertilizers. When symptoms appear, remove fruits immediately.
Plants usually grow out of this condition as the season passes. To prevent the problem maintain soil pH in the 6.3-6.8 range, mix in a handful of gypsum (calcium sulfate) into the planting hole prior to transplanting, keep plants well mulched and watered through the growing season, and avoid over-fertilization with high nitrogen fertilizers. It would not hurt to add 1/4 cup of gypsum to each plant at this time (scratch it into the top 1 inch of spoil around each plant).
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