Fish Fertilizer For Plants | How to choose and use on houseplants

Fish fertilizers are not new to the market. Centuries ago, when we do not have soil research techniques. The native American farmers develop fish fertilizers. They use dead fish in their farms to increase the fertility of the soil. They use it as a soil amendment.

Nowadays we have the strong technology to make excellent fish fertilizers.

But the question is,

Are fish fertilizers being good for plants?

How to use them in your garden?

What are the different types?

Which one is best for your plants?

In today’s article, I will explain every single detail about fish fertilizers. After reading this post you will not need more advice on fish fertilizers.

Let’s start the journey

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What is a fish fertilizer?

Plant fertilizer that is made by using dead fish is called fish fertilizer. Fish is the main and the only ingredient in this fertilizer.

There are 3 types of fish fertilizers, all of them have the same nutrients but in more or less concentration.

You can use fish fertilizer for your lawn, flower plants, vegetable, and herbs.

Generally, fertilizers made from fish contain the following nutrients.


Every plant needs some amount of nitrogen to grow. Green leafy plants and vegetables need a high amount of nitrogen. Plants need a good amount of Nitrogen to make their plant cells. They need it to make a good yield and also increase the quality of food.

Nitrogen-deficient plants do not grow healthily. They stop growing and die in few days.


Every single plant cell contains phosphorous. It is required for transportation functions. Phosphorous transfers the energy from one part of the plant to another parts.

It is required to transport the glucose and other sugars within the plant from roots to leaf tips.


It plays important role in plant functioning. Potassium is required to transport the water, nutrients, and carbohydrates to different parts of the plant.

It affects the production of essential protein and amino acids. Which directly impacts the quality of photosynthesis.


Calcium in fish fertilizer is required to help the plant maintain cell membranes’ health. Calcium helps to produce more new leaves in a short time.


This ingredient is required for the photosynthesis process. Magnesium help plants absorb the sunlight through their leaves. It is also required for the green color of the plant leaves. Magnesium-deficient plants look weak and fade in color.


Sulfur does the same thing that phosphorous do in plants. It acts as a helping agent of phosphorous.


It is not a mandatory nutrient for the good health of plants. It gives good support to the plant metabolism system and synthesis of chlorophyll.


It is required for the proper functioning of the plants. Many important functions like regulation of enzymes, chlorophyll, utilizing Nitrogen are all dependent on Iron in plants.

Fish fertilizer for plants also contains supporting nutrients like Copper, Zinc, etc.

Types of fish fertilizer for plants

Fish fertilizers are of 3 types. All of them have different uses, pros, and cons. Read the below part and decide which one is best for your garden.

Fish Meal Fertilizer

This is a type of fertilizer that is made from the by-product of the fish industry. When they take oil and protein out of the fish.

They through the remaining fish parts like bones, tails, fins, etc.

Fertilizer manufacturers buy this waste from the industry. They add enzymes in it and let it dry after that they grind the bones and dry parts of the fish.

The finished material is called fish meal fertilizer. It can be powdery and grainy depending on the demand of users.

Generally, fishmeal fertilizers are good for outdoor garden plants and lawns.

Fish meal is cheap to buy and is easy to use. Due to its low potency, it will not cause fertilizer burn.

Fish Emulsion

It is a liquid type of fish fertilizer.

Again, fertilizer companies buy leftover fish from the fish oil industry. They collect the material in one place and it has to go through a steam bath instead of the drying and grinding process.

In the steam bath process, they extract every single drop of protein from the fish waste. Then this liquid gets collected in a single container and your fish emulsion is ready.

Fish emulsion has more nutrients than fish meal fertilizer. Also, the emulsion is fast releases the organic form of nutrients.

Fish Hydrolysate

In Fish hydrolysate, the companies turn PURE FISH into liquid form without using the heat treatment.

They Cath the fish and by using a cold pressing technique they extract oils from the fish.

Because of the absence of heat, this type of fertilizer contains a high amount of top-quality nutrients. The heat treatment in the emulsion technique burns many important nutrients.

Fish hydrolysate is the superior and more concentrated form of fish fertilizers.

Before using it, you need to dilute it with water as per the manufacturer’s instructions. Using concentrated liquid will result in fertilizer burn.

Fish hydrolysate is costly than fish emulsion.

Benefits of using fish fertilizer

  • Fish fertilizers are non-toxic to pets, plants, and humans
  • They are 100% organic nutrients
  • Nitrogen, Phosphorous, and Potassium are the main organic ingredients.
  • Fish fertilizers are a good source of organic Nitrogen.
  • They do not burn the plants in case of overdosage.
  • Fish fertilizers make plants grow fast and develop a strong structure.
  • They increase the quality and quantity of yield.
  • They also contain many secondary nutrients.
  • Some manufacturers add trace elements in their fish fertilizer formula.
  • Fish fertilizers are best for plants

How do fish fertilizers work?

Modern fish fertilizers are different from ancient fish fertilizers.

Fertilizers like fish meal are in powdery form. Fish meal is a slow-releasing organic fertilizer. You cannot just give it directly to the plants.

You cannot use it on the container plants.

You have to mix the fish meal into the soil. There it gets decomposes and releases nutrients into the soil.

This process increases soil fertility and makes your garden soil workable. Mix fish meal 2 weeks before planting the seeds.

On the other hand, emulsion and hydrolyzed fish fertilizers are in liquid form.

They come in a concentrated solution you need to dilute them first before use. You can use these fertilizers on container plants, grow bag vegetables, raised bed flower plants, etc.

If you choose fish hydrolysate you need to pay a little more. But once you apply it to your plants you will see incredible growth.

Moreover, this fish fertilizer for plants also keeps the soil microbes happy. It gives them essential food to eat and they break down easily.

Soil that has a good percentage of healthy microbes is considered highly fertile soil.

How make fish fertilizer for plants at home?

If you have a low budget then you can make fish fertilizer for plants at home. Making a fish meal is simple you just need to collect the fish waste and grind it.

For fish emulsion, you need to do little work.

You will need fish waste, brown sugar, and an airtight container.

Mix the fish and brown sugar in an equal amounts in a plastic container. This process is similar to the bokashi composting process.

It will take 3 months to make hydrolysate fish fertilizer from fresh fish.

After mixing the fish and sugar in equal parts seal the container with its lid.

Leave the container for 90 days to let the fish ferment. After that your hydrolysate fish fertilizer will get ready for use.

Once the time limit finishes you should take out the mixture and use a big strainer to take out the large pieces.

Collect the liquid in the barrel and use this liquid after diluting it with water.

Do fish fertilizers release a bad smell?

Yes, homemade fish fertilizers release a bad smell. If you do not want your plants to smell like fish, you can buy ready-to-use commercially made deodorized fish fertilizer for plants.

Fish fertilizers for tomatoes?

If you are growing tomatoes at home. You should use fish emulsion fertilizer for good tasty tomatoes.

Tomatoes need a high amount of water and fertilizers to grow big and to develop a sweet taste.

Fish emulsion has everything that a tomato plant needs to grow and to produce a heavy yield.

In my experience emulsion is better than kelp meal fertilizers.

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