If you are an avid vegetable gardener, you'll benefit from making your own fish emulsion to fertilize your garden. It's less expensive to make your own fish emulsion than to buy commercial versions, and you have the benefit of being able to control exactly what goes into it, so it can be completely organic if you like. Fish emulsion has high nitrogen levels and phosphorus, potassium and trace mineral levels that are beneficial to vegetables.
Begin to break down the fish by putting it into the covered, airtight container. Both fresh fish parts and canned fish are acceptable. The type of fish does not matter.
Mix the fish in an approximately 1:1 ratio with the straw, sawdust or dry leaves. Mixing the fish with one of these ingredients helps speed the aerobic decomposition process.
Add a quarter cup of unsulfured molasses. This both promotes beneficial microbial growth and helps control odor.
Rip two to three dried seaweed sheets into small pieces and soak in a small amount of water until soft. Add seaweed and water mixture to fish mixture. Cover.
Allow the fish mixture to decompose, stirring it every few days to make sure new surfaces are exposed to air. Keep covered tightly at all times to avoid odor issues.
Apply fish emulsion to the soil in your garden about a week after you started to make it. By that point, it should be a paste-like consistency. You can mix it with water and spray it onto the dirt, or you can spread it lightly over the dirt in paste form and then water. This will help dilute the concentrated paste and spread the nutrients around.