Derived from fish byproducts, fish fertilizer -- sold as fish hydrolysate, fish emulsion or fish meal -- nourishes garden plants in various stages of growth. Applied to the soil or used as a foliar spray, this slow-release fertilizer supplies plants with nitrogen, phosphorous, potassium and micronutrients. While fish meal is a dry powder, both fish hydrolysate and fish emulsion are water soluble.
Container seedlings that are at least 3 inches tall and have at least two sets of true leaves can benefit from a feeding of fish emulsion. Dilute with water to half-strength according to package directions and apply just as if watering. To give transplanted seedlings a foliar feeding with fish emulsion, first choose a cloudy, cool day to avoid leaf burn -- preferably in the early morning. Add half of the recommended amount of liquid emulsion to a spray bottle or a sprayer and add the recommended amount of water to mix. Spray until leaves are wet.
Bud and Fruit Set
For flowering and fruiting plants, soil preparation is essential. An application of fish meal to the planting area supplies nitrogen, phosphorus, and potassium. During fruit set, a foliar spray can be applied using fish emulsion on an overcast day, mixing with water according to package directions.
Fish emulsion or fish hydrolysate may be used as a root drench or foliar feed throughout the growing season, particularly for vegetable gardens. For a root drench, mix the fertilizer at full-strength. Apply to root zone every two weeks. Spray a full-strength foliar spray in the early morning when clouds are forecast, once a month.
Vegetables, Herbs, Containers
Vegetables benefit from the nitrogen in fish fertilizers. Grow leafy lettuces by fertilizing with half-strength fish emulsion and apply as if watering every two weeks. Incorporate two tablespoons of fish meal into the planting hole when preparing the soil for garlic (Allium sativium). Garlic is hardy in U.S. Department of Agriculture plant hardiness zones 3 through 8. Keep herbs producing by applying a full-strength solution of fish emulsion or fish hydrolysate mixed with water every two to three weeks. Do the same for container plants, feeding every three weeks.