Thus, direct application of calcium to fruit is ineffective, although when applied to the foliage, it can help prevent the condition from occurring on developing fruit. Cultivars that grow quickly and produce large amounts of foliage tend to be more susceptible to blossom end rot. Therefore, reducing nitrogen levels will help reduce blossom end rot. Avoid ammoniacal forms of nitrogen that compete with calcium during uptake from the soil. Incidence of blossom end rot may also increase where there is a low ratio of calcium to certain other nutrients such as potassium and nitrogen.
Seedlings grown in the field at a steady rate are less susceptible to blossom end rot.
Also, windy conditions in the spring coupled with low relative humidity can cause the high transpiration rates, that can induce blossom-end rot. Fluctuations in soil moisture during periods of rapid plant growth create moisture stress and limit calcium distribution to the fruit. In addition, tomatoes, peppers and watermelon planted unusually early while the soil is still cold are likely to have their first fruits affected by blossom-end rot. Planting a bit later in the season helps reduce the problem. Removing affected fruits when symptoms are first observed may promote subsequent sound development of other fruit on the plant.