All fish emulsions are good organic nitrogen suppliers, but they also supply phosphorus, potassium, amino acids, proteins and trace elements or micronutrients that are really needed to provide deep nutrition to your soil community and plants. One of the benefits of fish emulsion is that they provide a slower release of nutrients into the soil without over-feeding all at once. It is usually applied as a soil drench, but some gardeners swear by using it as a foliar fertilizer as well.
Adding seaweed or kelp to the brewing process adds about 60 trace elements and natural growth hormones to the mix, really boosting the effectiveness of the fish emulsion. The seaweed or kelp transforms the emulsion into a complete biological fertilizer. Beneficial soil fungi love seaweed. Dried seaweed is available at most oriental grocery stores.
To make your own, obtain a dedicated 5 gallon bucket for this project. Trust me; you won’t want to use it for anything else once you’re done! Buy 10 cans of herring type fish such as sardines, mackerel or anchovies. Sourcing these from a dollar store or scratch and dent store makes perfect sense, as you don’t care about the can and aren’t going to eat them. Fill the bucket half full of well-aged compost, aged sawdust or leaves, or a combination of all three. Add water to about 2 inches from the top, put in the cans of fish, rinsing the cans with the water to make sure you get every last drop of the “good stuff”. The juices or oils in the can will breed beneficial microbes and supply extra proteins. To supercharge the brew, add 1/4 to 1/2 cup of blackstrap molasses to provide sugars and minerals to the fermenting process. The sugars also help control odors. Add the chopped or powdered seaweed to the mix. If you need extra sulfur and magnesium, add 1 Tbs Epsom salts. Stir well and cover with a lid to control the odor, but not tightly as it will build pressure as it brews. NOTE – Make sure that flies do not get into the bucket or you will have a marvelous breeding ground for maggots! One solution is to drill several holes in the lid for the bucket and glue screen mesh on the inside of the lid, allowing air flow but keeping those pesky flies out. Remember, you are brewing the most delicious aromas the flies have ever smelled! Let it brew for at least 2 weeks, a month is better. Give the contents a good stir every couple of days.
Once it has brewed for a month, it is ready for use! There are a lot of ways to use this brew, so be creative. Some folks will strain off the solids, put them in the compost pile and use the liquid as a concentrated “tea” to be diluted with water. Others keep everything together and stir the mix well before taking what they need. What you have is a supply of bio-available nutrients in a soluble form. For a soil drench, use 2 – 3 Tbs per gallon of water and apply to the roots on a monthly basis during the growing season. 1 Tbs per gallon of water makes a good foliar fertilizer. Just make sure to apply it by misting during the cooler parts of the day, not drenching the leaves in the heat. Half a cup per gallon will give your compost pile a kick start.
This brew will keep for at least a year, but you might want to make fresh each season. If you need less than 5 gallons, halve or quarter the recipe. It will smell, so store it where the odor won’t knock you out. I don’t trust the “deodorized” fish emulsions, as to remove the odor, some component of the fish product was removed either physically or chemically and is no longer available as a nutrient.