The best fertilizer for peppers is a balanced mix that contains equal proportions of nitrogen, phosphorus and potassium, such as a 10-10-10 mix, suggests the National Gardening Association. A mixture that contains too much nitrogen inhibits the peppers' growth.
A dose of dehydrated chicken manure or other animal-based organic fertilizer also benefits the peppers when added to the soil prior to planting.
Pepper plants that lose their blossoms before the fruit grows lack magnesium. By adding magnesium during the blossoming season, plant owners can help sprout a garden of peppers. A simple solution for a magnesium spray involves dissolving 1 tablespoon of Epsom salts in a spray bottle of water then spraying the solution on the plant's blossoms and leaves.