Fish Liquid Fertilizer: How Is It Made?

Organic growers are more careful about what and where their liquid organic fertilizers come from. Hence, this article discusses how liquid fish emulsions are made. First of, they are mostly made from the Menhaden fish which is not considered a human food source. However this fish is used for making oil and animal feeds. The waste from the production of this fish into oil or animal feed is the ingredient used for making liquid fish fertilizers.

How are liquid organic fertilizers made? The fish is steam-heated and then transferred to a large pressing equipment where the liquids and precious fish oil is rendered. All the solid substances are made into animal feed, while the oil is further refined into fish oil. As for the remaining liquids, it is simmered until it is transformed into a thickened fish emulsion. A small amount of phosphoric acid is added to the fish emulsion to lower the pH. Lowering the pH makes the liquid fertilizer more acidic, which prevents it from decaying and fermenting into gas. Before phosphoric acid was added in the manufacturing process, containers of fish emulsion were known to burst from fermentation. Because the amount of added phosphoric acid is so small (less than one percent by weight), the product is still considered organic.

Although formulations vary, fish emulsion liquid fertilizer typically contains approximately four to five percent nitrogen (N), two percent phosphorus (P), two percent potassium (K), and trace elements. Trace elements, also called micronutrients, are chemical elements that plants need in minute quantities in order to thrive.

Adventurous gardeners make their own liquid fertilizer from fish. It's a smelly, messy process, but it could be economical for gardeners with a ready supply of fish waste.

Liquid organic fish emulsions are an exception to other organic fertilizers because they release nutrients to the plant immediately. Hence, liquid fish emulsions are used for transplanting seedlings because it makes them more viable. To use as fertilizer, the liquid fish emulsion is diluted in water and sprayed on plants or used to water the soil.

As with the use of all fertilizers, application instructions should be followed strictly. Remember to dilute it in the recommended percentage to prevent damaging seeds and young plants. Only mix the amount you are going to use that day because after it has been mixed with water its potency will be lost when stored. And keep the mixture away from heat to prevent deterioration. Since its made from fish, brace yourself for the pungent odor but this will disappear in a few days.

Once again, we need to repeat that organic growers need not worry that fish emulsion fertilizer is depleting our oceans of the important Menhaden fish or other fish that people need for food. Fish emulsion if primarily made from fish waste of the established animal feed and fish oil industries, which would have been dumped in landfills if not used. The organic label in fish emulsion fertilizers not only means natural, it also means environmentally safe.

Note: For specific information relating to pastures, please go to our pasture fertilizer page.