How Fish Emulsion Is Made

Fish emulsions are thick, brown potent-smelling plant fertilizers. Emulsions are made from byproducts and waste from other processes. The material left behind after fish have been made into products like animal feeds and fish oil can be converted into an emulsion suitable for gardens.

Facts

While formulations vary somewhat, fish emulsions typically consist of 4 to 5 percent nitrogen, 2 percent phosphorous and 2 percent potassium. Trace amounts of other nutrients are also part of the chemical makeup. Gardeners select emulsions because of the high nitrogen content and because nutrients are released to plants almost immediately.

Rendering

Fish used to produce emulsions are not considered a desirable food source for humans, so the product is environmentally sound. Fish is steam heated to around 180 degrees F to kill off all bacteria. It is then sent through presses that squeeze out and draw off oils. Oils are used for other products and solids are sent off to be used for animal feed. The remaining liquid is kept for emulsions. This liquid is thickened through further heating that evaporates water.

Phosphoric Acid

A very small amount of phosphoric acid is added to the emulsion to stabilize it and arrest the decaying process. This also lowers the emulsion's pH slightly. Before manufacturers added acid to the mix, bottles on store shelves were known to burst from the gas buildup that resulted from natural fermentation processes. Although acid is used, it is present in such small quantities that fish emulsions are still considered organic and environmentally safe.

Product

Manufactured fish emulsions are basically a concentrated fertilizer that needs to be diluted with water before it is used on plants. The bottle's label will display instructions for cutting the product. Once mixed, the emulsion is ready to be applied to leaves or directly onto the soil around plants. Fish emulsions--even diluted--have an odor, but this dissipates after a few days.

Considerations

If fish emulsions were not made from the byproducts of other processes, it is likely these substances would end up in landfills. Some gardeners try to make their own emulsions by boiling fish and using the liquid left behind. While these home brews can be effective, they are not likely to be as cost-effective or as stable to store as a commercial emulsion.

References

• Best-Organic-Fertilizer.com: Fish Liquid Fertilizer
• Dramm.com: Fresh Water and Ocean Fish Emulsions
• AcornOrganic.org: Fish Products