Is Fish Oil a Good Fertilizer for the Garden?

Fish oil is an organic and environmentally safe fertilizer. Organic gardeners use fish oil, or fish emulsion, as a liquid fertilizer or as a foliar spray because it contains the three basic plant nutrients; nitrogen, phosphorous and potassium, plus micronutrients that plants need in small quantities to survive. Fish emulsion must be diluted in water before use. Dilute only the amount needed for immediate use, as potency will be lost when the diluted solution is stored.

Fish oil is high in nitrogen and is an excellent foliar spray when plants need a quick energy boost. Foliar sprays are absorbed directly by the plant and usually provide immediate results. Dilute fish oil in a spray bottle and spray directly on plant leaves and stems. According to the University of Rhode Island Cooperative Extension Education Center, the best time to apply foliar sprays is in the "early morning or at dusk."

Unlike other organic fertilizers, the nutrients in fish oil are released immediately upon application. This makes fish oil an excellent choice for use in transplanting seedlings to give them a good start. It may also be used as a supplemental feeding throughout the season.

Homemade fish emulsion costs less and contains more nutrients and beneficial microbes than commercial brands. Make your own fish emulsion instead of purchasing commercial products by composting canned or raw fish in a 5-gallon bucket filled ? full of sawdust, straw or leaves, which help control the fishy odor. Add molasses to build microbes and speed up the decomposition process, and a couple tablespoons of Epsom salts to add sulfur and magnesium. Compost the mixture for two weeks, stirring at least once a day to encourage aerobic microbial growth. Once the mixture is fully composted or decomposed, place some in a stocking with seaweed, to add trace minerals and disease controlling properties, and place in a gallon of water, with a few drops of mild liquid soap or liquid molasses to get better coverage from your foliar spray. Steep for at least a week or add an air pump to speed the process to about three days. Dilute solution for use as a liquid fertilizer or foliar spray.

Commercially made fish oil is an environmentally safe fertilizer, made from the waste of menhaden fish or other fish used in animal feed and the fish oil industry. These waste products would otherwise be dumped into landfills and are not fit for human consumption.