Jack's Professional 21-7-7 Acid 25lb. Fertilizer Water Soluble Plant Food This is an ideal fertilizer for acid-loving plants in the nursery and landscape Provides a rapid correction of a high pH situation Unlike other brands, Jack's 21-7-7 Acid contains no harmful chlorides Jack's Acid is a water-soluble fertilizer designed to be mixed with water for the most accurate and effective nutrient delivery to the plant.