Peter's 10-30-20. 1/2 Pound. Blossom Booster Water Soluble Fertilizer with Micro Nutrients. This offer is for 1/2 Pound bag. Peter's 10-30-20. Blossom Booster Water Soluble Fertilizer with Micro Nutrients. Peters Professional Blossom Booster is a specially developed water soluble fertilizer designed exclusively for flowering plants including orchids. It particularly stimulates the development of flowering buds. May be employed as a foliar spray and or drench plant/soil. Use for indoor and outdoor plants. For general purpose use mix 1 teaspoon per gallon of water. Use periodically throughout the season. Helps increase flower quality, size and number of flowers.