Gelatin Powder for Plants – Is it a Good Source of Nitrogen?

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Robert Pavlis

Social Media is convinced that gelatin powder is a great fertilizer for plants. It is easy to use, organic and has a high level of nitrogen. Seems perfect for houseplants and the garden.

Is this just another myth or is there something to this advice?

gelatin knox fertilizer

Gelatin Powder Fertilizer

What are the claims for gelatin powder?

“a houseplants best friend …. add vigor and new luster to your Boston ferns, African violets, colorful caladiums, or any other of your household favorites”

“gelatin has been found to be an excellent time-release fertilizer; a natural, nonpolluting, non-burning source of nitrogen.”

“Pure unflavored gelatin can be used as a homemade organic fertilizer” “Just dissolve the unflavored gelatin in hot water, let it cook and dilute it with plenty of water and you have a nearly all nitrogen liquid fertilizer”

“While unflavored gelatin provides lots of nitrogen, most plants need phosphorus and potassium too.   Add phosphorus and potassium to your plants by chopping up all of your banana peels and putting them in a jar of water. “

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“You simply pour it into the potting soil once a month without risk of overfeeding or fertilizer burn”

Lets have a closer look at these statements.

No risk of burning or overfeeding and yet it is “nearly all nitrogen”? How can it be both? Oh I see, you add it to water and “dilute it with plenty of water” and then claim it is still “all nitrogen”. What about the water part which is the majority of it?

Gelatin powder will add vigor and luster to plants, but such claims never define what this means. How much more does it grow? And what is a “non-burning source of nitrogen”, and why is that important for a garden?

It provides nitrogen, but if you want some P and K you need to add it – so clearly gelatin powder is NOT a fertilizer.

These are social media claims, but what are the facts?

What is Gelatin?

Gelatin powder is a derived from collagen taken from animal body parts. It is a mixture of peptides and proteins that contain carbon, hydrogen, oxygen and nitrogen. Zero phosphorus or potassium.

It is used as a thickening agent in such products as cosmetics, face creams, shampoos, marshmallows, ice cream and photographic film.

Nitrogen in Gelatin

How much nitrogen is in Gelatin? Based on the molecular formula for gelatin, C102H151N31O39 , it contains 18% Nitrogen and this is confirmed by Encyclopedia of Food Science and Technology.

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Preparation of Gelatin Fertilizer

A common recommendation for mixing the fertilizer is one packet per quart of water, but I have also seen suggestions that adding one packet to a rain barrel works.

One packet of Knox gelatin contains 7 g, which is 1.26 g nitrogen. A quart of water is 950 ml, or 950 g. That is a 0.13% solution, or an NPK of 0.13-0-0. A very weak source of nitrogen.

Does Gelatin Powder Work?

It is certainly not a fertilizer since it contains no P and K. But does it make plants grow better?

Adding gelatin capsules next to seeds does increase shoot growth: “treatment with two gelatin capsules placed adjacent to each seed increased shoot dry weight of cucumber, pepper, broccoli, tomato, arugula, and field corn, by 138, 244, 50, 45, 41, and 18 percent, respectively “, and  “there was a positive linear relationship between the number of gelatin capsules from 0 to 3 capsules on plant growth and plant nitrogen content.”

Since gelatin is a protein, we can expect bacteria to decompose it and turn it into ammonium or nitrate ions, which plants can use. It really is no different than any other type of organic matter. This makes gelatin a slow release nitrogen source, but probably not as slow as other hard to digest sources like fall leaves.

The amount of nitrogen in the above mentioned mixture is very low. No doubt it helps plants but you can expect the effect to be small. It could be used for a couple of houseplants, but seems very impracticable for the garden. There are many cheaper sources for nitrogen.



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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

11 thoughts on “Gelatin Powder for Plants – Is it a Good Source of Nitrogen?”

  1. I am going to experiment making my own slow release fertiliser using gelatin. I will make a mix of npk, micro elements, and amino acids.. add that to the water with gelatin and let them set. Then divide into capsules and burry in the soil in pots.
    Will take note of the ratios, and results.
    If anyone had tried this before lemme know.

  2. In addition to gelatin, If you added L-Trytophan to give it a complete amino acid profile, and then also added MSM and a B complex vitamin, do you think a tomato plant would benefit vs. a typical store bought organic nitrogen source?

  3. Hi, question regarding add banana peel to water, is it ok to add to the water with gelatin mixture? How long do you keep banana peel to water?
    Thank you, Sue

  4. Hello Robert. Enjoyed your article re gelatin as a fertilizer. I d never heard of that recommendation before.
    But in the article, you stated that it is ‘not’ a fertilizer, since it contained neither P nor K.
    I have excessive P and K in my soil, as confirmed by soil tests. So I primarily use ammonium sulfate as my source of Nitrogen. I call it a fertilizer. It is not a compound fertilizer containing P and K, but I certainly consider it a fertilizer. What would you call it, an amendment?

    • Try finding an accepted definition for fertilizer or amendment. Wide range of definitions. Some consider a substance to be a fertilizer only if it contains all three of the essential nutrients. A legal definition requires it to have the NPK on the label.

      In social media people use the term to describe a balanced plant food and think any ‘fertilizer’ is all your plant needs. It should at least have NPK.

      I guess you could call it a nitrogen fertilizer.

  5. Hello
    Why use gelatin as expensive source, not available fast to plants, when is way to buy Organic origin Nitrogen in Nitrate form. Which works fast, very well available for plants and price not expensive.

  6. I was wondering if you have ever thought of doing a post on using woodchips and whether or not it causes a “nitrogen draft.” I would be very interested in what you find out about that. Thank you.


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