How to Make Organic Fish Emulsion for Your Garden

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What You'll Need
Fresh or canned fish
5 gallon bucket with tight-fitting lid
Browns, like sawdust, leaves or straw
1 to 2 tbsp. molasses
1 to 2 tbsp. apple cider vinegar (optional)
1 to 2 tbsp. Epsom salts (optional)

Homemade organic fish emulsion is great for your garden because it’s cheap, has many nutrients and contains aerobic bacteria which are essential for disease control and soil health. It is a powerful agricultural fertilizer high in organic nitrogen and soluble phosphorous and potassium, which benefits as a foiliar feed. It’s cheap, has many nutrients and contains aerobic bacteria which are essential for disease control and soil health. When you make your own fish emulsion, you can also control the trace elements added and the growth of the microbes to suit the needs of your plants.

TIP: Our expert gardening advisor, Kathy Bosin adds, "Fish scraps, shrimp and crab shells can be safely added to your compost pile directly. Be sure to dig them deep inside your active compost pile to keep wildlife out."

Step 1 – Prepare the Fish Mixture

First, fill the bucket halfway with the "browns." Add the fish and the molasses, and then blend the ingredients together. The browns help to control the offensive smell while also absorbing any organic nitrogen so that it doesn’t evaporate. The molasses is important as it not only helps to control the odor, but it also builds up beneficial microbes in the fishy mixture to accelerate decomposition.

Seal up your bucket with the tight-fitting lid. Closing up the bucket and sealing it serves to control the environment in which the microbes will grow.

If you are using canned fish, let it decompose separately in a different container with some good soil and finished compost before you use it with the browns and molasses. This ensures that the preservatives don’t kill or harm any of the good microbes you’re trying to get in your paste. These chemicals could also harm your compost pile if put there before being allowed to break down.

Step 2 – Stir it Up

Every day or two, take the lid off your bucket and stir the mixture. This puts air into the emulsion for better microbial growth and decomposition. Let this paste rot for at least 1 to 2 weeks.

If you wish to mimic acidity and add trace elements found in commercial fish emulsions, you can add apple cider vinegar. If you would like to add extra magnesium and sulfer, Epsom salts. Either ingredient is acceptable, and both leave beneficial trace elements in your emulsion. Recent studies also show that unsulfured molasses or dry powdered molasses are best for microbial growth in compost tea brewing. As a result, if you plan to make a compost tea, unsulfured or dry powdered molasses can be beneficial to you.

Step 3 – Compost Your Emulsion

You can now safely add your fish paste to your hot compost pile or to your favorite compost tea recipes.