How to Make Fish Emulsion Fertilizer

This simple recipe for homemade fish emulsion is a great way to use scraps left after cleaning your catch, although you can use whole fish, too.


Image by Lorri Lang from Pixabay

Fish emulsion is a good fertilizer for lots of garden vegetables—and other plants, too. It has an N-P-K ratio of about 5-2-2, and has micronutrients, too.

Store-bought fish emulsion is made from the by-products of fish used for another process, like for making fish oil or canned fish. Using fresh fish that still have all their parts intact should be even better than the commercial stuff.

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How to Make Fish Emulsion Fertilizer

How to Make Fish Emulsion

You can make homemade fish emulsion at home in a bucket—or in several buckets if you have a lot of fish. I’ve done this with scraps I had from cleaning fish I caught, but it should work fine with whole fish, too.

  1. Fill the bucket about 2/3 of the way full by layering fish scraps and brown organic matter (like leaf litter) in equal parts. If you’d like, add molasses and seaweed to get more nutrients in the emulsion.
  2. Fill the bucket with water to cover all the material; cover it with a lid; and keep it out of the sun.
  3. Stir the mixture every few days for several weeks, and then it should be ready to use.
  4. Pour off the water and catch it in another bucket—this is your fish emulsion. You can use the remaining fish scraps and leaf litter to brew another batch, or just put them in your compost pile or worm bin.
  5. To use the fish emulsion, dilute it with water. Use about a cup of emulsion to a gallon of water. The dilution can be used to pour on garden soil or to spray on leaves.

What Do You Think?

What’s your favorite way to use fish emulsion? Have you successfully made it using other methods? Let us know in the comments below!


This is an updated version of an article that was originally published on March 30, 2015. The author may not currently be available to respond to comments, however we encourage our Community members to chime in to share their experiences and answer questions!

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  • Sally says:

    Lettuce doesn’t sweeten up without fish fertilizer and I wondered how to make it (without creating something noxious). So thank you for the useful fish fertilizer recipe!

  • Stphen says:

    Fish fertilizers are also good and provide better benefits for our plants. Apart from chemical fertilizer fish fertilizer and organic fertilizers are good for crops and plants; fish fertilizer contains different types of beneficial ingredients and here we have found some homemade fish emulsion with the mixture of seaweeds and other organic products. I hope we should learn some better techniques of preparing homemade recipe fertilizer from fish and other organic products.

  • Edward Lye says:

    Seems to be a whole lot of work to prepare this. Anyway I never have any leftover fish bits after we and the cat go through them but if I envisage getting a windfall of unfit to sell fish from the supermarket I might just roughly chop/food_processor it and freeze in ice-cube trays and bury an ice-cube as and when I need to.
    As you can imagine, I don’t like to spend too much time/effort/space/material on something that nature can readily deconstruct. I believe the native American Indians planted corm this way sans the refrigeration bit.

  • karen says:

    i have a large bag of fish bones, heads and tails in the freezer waiting to make stock. but i really dont like fish stock. How can I use in the garden?

    1. tlogan says:

      Seems to me that those would be perfect for this recipe!!

  • AlexandraPanzer says:

    A stinky process but probably the best fertilizer I have found in years of gardening. Using this I harvested the best crops of garlic, sweet potatoes, ginger and turmeric I have ever produced. It took me a few tries to get my method down – decanting it after a few weeks of fermenting can be a choking experience. I wear a bandana mask and put a few drops of eucalyptis essential oil on it. Rubber gloves, old clothing, and directly to the showers afterwards, leaving a pungent trail of scent behind me and my husband holding his nose.. I used to buy fish emulsion that cost $50 a gallon. I can make 5 gallons for no cost – though I purchased $18 worth of fish carcasses from a local seafood place once. Even that was worth it. If you go down to a local marina when the guides come in at the end of the day you can load up as many buckets of carcasses as you please for free.

    1. Bobbie Jo says:

      I wonder if the fish emulsion would help with my sweet potato’s flavor. I can grow sweet potatoes just fine, but they’re tasteless. I also wonder if I harden them off improperly. I see some information stating it needs to be 80 degrees and some sources say 100 degrees. Some sources say ten days, others two weeks. I tried ten days in my oven with the light on keeping the sweet potatoes at about 90 to 100 degrees. Oh, I fed the soil with a landscape mix that had pine bark, peat and something else. I also gave the soil worm castings and Azomite, a rock dust. That didn’t work. Any suggestions?

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