FoxFarm Bush Doctor Wholly Mackerel is a liquid plant nutrient derived from marine fish species and is an enzymatically digested product. It provides readily available amounts of organic nitrogen, phosphorus and potassium to growing plants. These nutrients are available to plants when used as a root drench application or when applied as a foliar spray. The proteins in Wholly Mackerel are pre-digested into readily usable peptides for plants and soil microbes. CDFA Registered for Organic Gardening.