Jacks Classic No.1.5 10-30-20 Blossom Booster Fertilizer. Blossom Booster 10-30-20 is a Professional formula designed to produce more flowers and brighter colors on all indoor and outdoor plants. All indoor and outdoor flowering plants like: geraniums, impatiens, begonias and marigolds. Feeds through both the roots and the leaves. This is the Original Blossom Booster with the proven 1:3:2 nutrient. Great for vegetables and fruit. Can also be used as a transplant solution.