Could be a number of reasons ... A common ailment with capsicum is blossom-end rot. This condition just effects the fruit and not the plant blossom or flower. The condition gets its name because the symptoms appear at the ‘blossom end’ of the fruit. The first sign of blossom-end rot is that the end of the fruit becomes off-whitish to brown in colour and takes on a ‘sunken in’ appearance. As the fruit matures, these symptoms become more pronounced and the colour of the rot becomes dark brown to almost black. Blossom-end rot is caused by insufficient calcium supply. However, the most common cause is from irregular watering during the critical growing period of the young fruit. Even when calcium levels in the soil are sufficient, a plant receiving insufficient or irregular water will have difficulty absorbing and delivering calcium to the fruit. To control blossom-end rot. Boost the soil with calcium by adding lime, dolomite, gypsum or composted animal manures before planting the seedlings. Water regularly. Most capsicum crops continue to flower and bear fruit for prolonged periods of time, so ensure the soil around their roots is kept moist. Avoid fertilisers with a high nitrogen content. Nitrogen fertilisers will promote leaf growth at the expense of fruit, allocating calcium to the leaves instead of to the fruit.

- ej