During the flowering and fruiting stage, your plant's nutritional needs will change. Their desire for high amounts of nitrogen will diminish, replaced by the increased need for flowering nutrients such as phosphorus and potassium. Potassium is important for good fruit development, and inadequate amounts will cause fruit and flower drop. Phosphorus is vital for photosynthesis and flowering. At the beginning of the flowering stage, plants should be fertilized with flowering nutrients at each watering.