Tomato Blossom End Rot
Blossom End Rot is a physiological disorder caused by lack of, or irregular watering, and an imbalance of potash and calcium.
It appears as a brown spot at the base of the fruit, this develops into a hard, sunken ring.
The problem generally occurs at the early part of the season when the plants are rapidly producing fruit and there moisture and calcium needs are at their highest.
Once a fruit is affected there is no cure, but further occurrences can be prevented by ensuring that the compost never dries out.
Plants may need watering both morning and evening to prevent this becoming a problem.
Avoid high temperatures as this will increase the plant's transpiration rate
If plants are allowed to dry out, this will inhibit root function, which in turn impairs nutrient uptake, meaning, plants in containers and grow bags are especially prone.
Over-application of high-potassium tomato fertiliser inhibits calcium uptake thus contributing to the problem.
Foliar feeds of calcium nitrate will not help and can scorch foliage.
Other types of plants that are susceptible to blossom end rot include; Aubergines, Sweet and Chilli peppers.