Complete Guide To Fish Fertilizer

Complete Guide To Fish Fertilizer

Fishing Emulsion is considered an organic fertilizer. It’s made popular by toting results in both foliage display, flowers and overall yields. This Gardening In Canada article takes a look at fish emulsion to figure out the pros and the cons of using it. We will be looking at how to make fish emulsion and also the fine line it walks when determining if it’s organic or not. Lets jump into a complete guide to fish fertilizer.

If you are new to this blog my name is Ashley and I am a soil scientist. I am located in a Canadian Zone 3 and a USDA Zone 4. I write articles and make YouTube videos all designed for Canadians and Cold Climate gardeners using science based methods. If you are looking for anything specific be sure to let me know in the comments down below

What is fish emulsion?

The first step in analyzing anything is understanding exactly what it is. Fish emulsion is The same as fish fertilizer. All forms of fish fertilizer that is liquid can be categorized under this term. As a result concentration of N-P-K may vary but that is due to the processing not the fertilizer name. 

Keep in mind that while fish fertilizers are OMRI approved, they are made using small levels of phosphoric acid and “scent aids”. The acid is less than 1% of the total volume of liquid and is used to help with the degradation of the fish parts.

Why Is the N-P-K Low?

The N-P-K values are typically 5-1-1 on any fisher fertilizer product. And this is because the bioavailable components of the product are 5% nitrogen, 1% phosphorus & 1% potassium by volume. The product’s volume is mostly water and a combination of larger molecules that are not yet degrade. For more on fertilizers check out this article.

Over time these molecules will be broken down by the soil microbes and turned into usable nutrients. This makes fish emulsion more of a slow release fertilizer in the long term. As a result when you use fish emulsion in the garden you want to make sure the microbes are happy and healthy.

Soil Microbes And Fish Emulsion

A complete guide to fish fertilizer would not be complete without discussing the importance of soil microbes. As a result you absolutely need healthy soil when using any organic forms of fertilizer. This is why fish emulsion should be used in combination with a soil amended with organic matter. Consider adding fresh compost and mulch at the beginning of every new growing season. This will help increase the soil’s natural moisture and feed the microbe populations.

Is Fish Emulsion A Full Fertilizer?

Remember fish fertilizer is a full fertilizer when it comes to the basic nutrients N-P-K. In some cases the product can have some additives that increase the micronutrient concentration. However, when it comes to the basics, fish emulsion is able to cover the full spectrum, for instance.

One of the benefits to fish emulsion is the addition of Sulphur, magnesium and calcium. All three of these micronutrients are essential for plant growth and production of healthy plants. Many organic and even conventional fertilizers are missing these key elements.

What The Studies Say About Fish Emulsion

I go into the studies with a bit more detail over on the YouTube video but there are three main highlights. The first one being an increase in both EC (electric conductivity) and the pH. As a result this increase is slight but can be beneficial if you have an acidic soil that is limiting nutrient uptake. Fish emulsion increasing the pH can actually place the soil into an optimal range for solubilizing nutrients. This range is 6 – 7.5 and most potting soil mixtures naturally sit much lower. 

Other studies with fish fertilizer looked at the upper and lower biomass of the plant. It has been found that the upper biomass is commonly less robust then the root systems. And this may be due to the lower values in phosphorus and potassium, The best way to counteract this is with the use of supplemental fertilizers. This can be in the form of an organic or conventional fertilizer.

Is There Mercury In Fish Emulsion?

Yes, there is mercury in fish emulsion. However, remember mercury is naturally occurring in nature, so the real question should be does it affect your garden produce. The best way to look at this is through the lens of whether or not a plant is a hyper accumulator. The concept of using plants for phytoremediation is not a new idea and is a well understood mechanism. Unfortunately a complete guide to fish fertilizer needs to talk about this pretty major flaw.

Some garden plants that have the affinity for mercury include:

  • Amaranth
  • Lettuce
  • Water Spinach
  • Tomatoes
  • Peppers
  • Cucumbers

This means if you are using fish emulsion or fish fertilizer with these crops you may want to consider using a lower volume. Using fisher fertilizer with these crops is completely accepted as a form of fertilizer. The key is to use caution and a combination of different fertilizer forms.

How To Make Fish Fertilizer At Home

This process is not for the faint of heart. And to be totally honest the smell was too pungent for me to even finish. About a month into the process the entire project was scrapped; This is mostly because I was confident the neighbors were about to start calling the cops.

  1. You will need a fish or parts of a fish from a recent fishing trip. This doesn’t need to be a whole fish, bits and bobs will be just fine.
  1. Next cut what you can into small one inch chunks. And for the parts that can’t be chopped up either leave them or if you can stomach it place them into a blender.
  1. Add water. Fill the five gallon bucket right to the top.
  1. Pro Tip: Try adding a DIY Lactobacillus mixture to the bucket. For more on this check out this article.
  1. Add 3 cups of sugar. Any kind will do.
  1. Now stir everything together.
  1. Loosely cover the container. It is important that you do not seal it because the fermentation will cause pressure build up, for instance.
  1. Now you simply wait for a month or more. 
  1. You know when it’s done when there is no smell. This is officially ready to be used and a cup can be mixed with a gallon of water.

Fishing Emulsion is considered an organic fertilizer. As a result it has been made popular by toting results in both foliage display, flowers and overall yields. This Gardening In Canada article takes a look at fish emulsion to figure out the pros and the cons of using it. We will be looking at how to make fish emulsion and also the fine line it walks when determining if it’s organic or not.

2 thoughts on “Complete Guide To Fish Fertilizer”

  1. Hi Ashley,
    My name is Janice and I live and garden in urban Cambridge, Ontario. I used fish emulsion this year on my flower planters and gardens. We also have a 55 gallon fish tank that requires water changes every one to two weeks. The water that comes out of the tank goes directly onto what ever garden I feel like at the time. In the winter, it’s whatever garden is easily accessible that day……lol. I’m just wondering if (fresh water) fish tank water can act similar as fish emulsion. I figure it can’t hurt, there’s definitley not mercury in the fishtank water, so that’s a good thing, Right?? :0) The reason I purchased soil emulsion this year is because our veggie garden seedlings were being dessimated after they were planted outside. I think we had a bad case of those little hover flys or gnats maybe, and we likely had them indoors and took them outdoors and they just proliferated. Things got off to a very slow start, but I thought the fish emulsion could help. And I’m just wondering if there’s any benefit to adding fish tank water, if that could be just as good as fish emulsion??

    My brother in-law is a Professor/Doctor of soil science at the Brandon University……Dr. Alex Koiter……lol….we call him Doctor Dirt, and then he corrects us and says Dr. Soil…….lol, the kids love it! I just thought I’d mention him since you are a soil scientist as well :0)

    Thanks for the awsome info!
    Janice

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