We’ve all heard about fish emulsion, but what’s really in it and how does it actually work in the garden?
Proponents claim that fish emulsion is an excellent slow-release fertilizer, especially for delicate seedlings, providing a gentle dose of nitrogen. Fish emulsion is organic and nontoxic.
Some of the down sides of using fish emulsion are cost and smell. Let’s face it, dead fish have a pretty short half-life. The smell may also attract some unwanted wildlife, such as skunks and flies. Some fish emulsion manufacturers claim that their product is “non-odorous”. I can’t imagine how that happens, but maybe.
Now, most commercially available fertilizers range in significantly higher numbers than fish emulsion, when it comes to nutrients. If you recall, the NPK numbers found on fertilizer packaging refers to the percentage by weight of nitrogen, phosphorous, and potassium, respectively. Commonly, the nitrogen and potassium numbers will be in the double digits, while phosphorus is usually a single digit number. For fish emulsion, the numbers are much lower. The NPK ratio of fish emulsion ranges from 4-1-1 to 5-2-2. This is neither good nor bad, it simply shows that the nutritional value of fish emulsion is lower than many other sources of plant food.
The science behind fish emulsion studies has come to some specific conclusions:
So, the bottom line on fish emulsion: it is an effective way to feed delicate seedlings and transplants, providing easy to use nutrients, but it doesn’t do much of anything for larger, more mature plants.
In my book, I categorize fish emulsion as a plant baby food.
Have you used fish emulsion successfully? Let us know in the comments!
I hope this information inspires you to grow more of your own food. You can ask your garden questions on my Home page.