Make Your Own Organic Plant Fertilizer for FREE





Introduction: Make Your Own Organic Plant Fertilizer for FREE

About: I find enjoyment is all kinds of things. My interests range from off-grid living to gaming. I've always enjoyed making something out of "nothing". I have 3 young children and am often thinking of ways to inc...

When thinking about plant fertilizer it is of course important to understand what a plant needs in order to survive and thrive. Without getting overly complicated (there are many articles out there there that go in depth into the nutritional needs of various plants) there are three main elements a plant needs: nitrogen, phosphorus, and potassium (you'll often see this referred to by gardeners as: N-P-K). And did you know that you likely throw these things away in your home in abundance? Let's follow one of the three “R's” of recycling (reuse) and put those to use to make a 100% organic slow release plant fertilizer that will likely cost you NOTHING.


* used coffee grinds

* egg shells

* banana peels

* 4 containers (used containers from grocery items work great or mason jars if you prefer them): 3 to store the above items in and 1 for your final mixture that you'll feed to your plants

* Cookie sheet

* Cooling rack (optional)

* A means of dehydration (I'll discuss free options and other alternatives in this tutorial)

* A coffee grinder (either an electric coffee grinder or hand crank coffee grinder)

Now that you have everything, let's get started!

For those who are more visual I've made a quick video:

Step 1: Coffee Grinds

Coffee is full of our first nutrient: nitrogen!

One of my favorite things is when I can find multiple uses for one item. After I brew a pot of coffee in my house I spread those used coffee grinds onto an old cookie sheet and place it in the sun to dry (outside or a sunny window is fine). Used coffee grinds dry quickly in the sun. Mine are usually done within 1 day, maybe 1 1/2 if it's not so sunny.

Once dry you can either store this in a container or you can grind it further in your coffee grinder into even smaller pieces before storing. The advantage of grinding it down to as much of a power substance as possible is that you're creating maximum surface area for you plants to draw the nutrients from.

Step 2: Egg Shells

Egg shells are full of our second nutrient: phosphorus!

I place my used egg shells in a bucket (an old ice cream bucket or anything similarly sized that you have) and place that bucket in the sun to dry just like we did with the used coffee grinds. I have heard of people washing the shells to prevent any bacteria from growing, but I've found that to be unnecessary as long as you're drying them out right away in good sunlight. I suggest you do what feels right to you.

Once dry grind in your coffee grinder as fine as you can and store in a container.

A side note: the egg shells will smell a little unpleasant when you begin to grind them (nothing unbearable) whereas the coffee and banana peels smells wonderful! Just a friendly warning.

Step 3: Banana Peels

Banana peels are full of our final nutrient: potassium!

Simply place your used banana peels onto either a cookie sheet or a cooling rack and place in the sun. I prefer the cooling rack as it maximizes the air flow helping the peels to dehydrate better, but use what you have! If you don't have a cooling rack there's no need to run out and buy one just for this. These will take 1 to 3 days to dry depending on the amount of sun and wind you have.

You'll know they're dry when they're brittle and easily break apart (they'll also turn black). Break them apart and place into your coffee grinder and grind as fine as you can and store in a container.

Step 4: Optional FYI: Alternatives to Sun Dehydration

I live in the northern Mid-West. The sun isn't always efficient enough for outside or even window dehydration. You have two alternatives during these weather conditions: a commercial dehydrator or you can simply use your oven.

To use your oven it's as simple as setting your oven to 120 degrees F. Drying times vary (as much as up to several hours for the banana peels because they start out so moist) so check them often. Remember we want to dry, not cook. Feel free to try this method if sun drying is not an option.

If you have a wood stove simply placing the items within close range of your wood stove would surely do the trick as well!

Step 5: Mixing Your Three Nutrients

Different plants desire a different amount of certain nutrients. However, nearly all will be perfectly happy if you simply combine these in equal parts. (If in doubt, research first!) So grab another container, measure out an equal portion of each of the three items we made: ground coffee beans, egg shells, banana peels, and mix well!

Step 6: Feed Your Plants

This is a slow release plant fertilizer. So in other words as it sits on (or in) the soil it will slowly release into the soil and your plant will feed on these nutrients (unlike a liquid fertilizer which reaches your plant much faster). Having said that if you're re-potting a plant (such as a seedling) mixing a small amount into your potting soil (I would say no more than a couple tablespoons per 1 pound of potting mix) and then simply sprinkling the top soil once every 2 – 4 weeks with more of your mixture should be well more than enough fertilizer for most plants. Keep in mind that over fertilization is just as bad as (if not even worse than) under fertilization. Less is always more, don't over do it!

Save money, energy, and recycle! And last but not least.... happy growing!

Finally, make this a fantastic and fun learning lesson to share with your young children or classroom by visiting: The Homeschool House

Step 7: Some Final Notes About Organic Foods

It's important for me to note that the final product is only going to be as organic as the materials you've used (the coffee beans, egg shells, and banana peels). For those interested I'm including links concerning pesticides and how they're used for each of these items for you to educate yourself and choose what you feel is right for yourself, your family and in turn, your plants.

Banana Cultivation Is Pesticide-Intensive

Are You Sipping Pesticide Residues In Your Morning Coffee?

Are Some Eggs Safer Than Others?

Live off the Land Contest

Second Prize in the
Live off the Land Contest



    • Stick It! Contest

      Stick It! Contest
    • Make it Move Contest

      Make it Move Contest
    • Casting Contest

      Casting Contest

    We have a be nice policy.
    Please be positive and constructive.




    Great Instructable! Good, clear instructions.

    What ratio of coffee to egg to banana peal.?

    1 reply

    Go to a Starbucks or Peet's or any coffee house and ask them for grounds. They have them by the pounds and are happy to give them away.

    1 reply

    it is too much expensive when use Coffee as source,
    Is there an altertive way?

    1 reply

    Coffee grinds which are being used here are the residual of proper coffee. If you use some "instant" coffee, then you don't have the residue.

    We have an outside sink with a garburator in the bottom of it, like is in lots of kitchens. There is just a short pipe for the discharge and we have a bucket under it.

    We put our compost stuff in the sink, turn on the water and flip the switch. When the bucket is near full we stop motor and stop water. either get another bucket or take and dump this one on the garden or on shrubs or fruit trees.

    I put these ingredients into my "super blender" with a little water or very wet veggie stuff and spin until perfectly smooth then pour into the compost pile.

    The finer the ingredients, the easier it will compost.

    Every morning, my breakfast is a banana and a coffee. I put this in my compost. If you are using coffee cartridge in paper, you can put them full in your compost.

    Worms loves paper !

    Just a little note, NPK is a mathematical way to see plants. Plants needs more than NPK, they need minerals, they need mushrooms and they need other plants and animals to live. They are connected ! If you want a beautiful garden take a look at permaculture stuff :)

    farticus, you are absofrigginglutely correct, it does make an xcellent source of protein for worm farming, & you do not have to dry things out or grind them into dust to get the job done, ...

    Veggie plants, need calcium to to keep end blossom rot from occurring, & egg shells are a great source for that, ... & indeed the coffee grounds also are great for the nitrogen content, & the ahah! Moment will come by using the banana peels, as well as an over ripe banana will also provide the necessary sugars to give your worm farm the sustenance also needed for stimulating root growth, ... as the worms will turn just about anything they can digest into worm castings, which is a truly great "organic" source of food for both the worms, & plants, ... another great item that I have found that my leaf worms are thriving on is the leftover corncobs, from our latest BBQ, ... it takes about a month & a1/2, but leaves the soil in great condition, & I have xpanded my operation to 4 of those foam box containers that I get my diabetes drugs delivered to the house, ... lI try to re-use just about everything, ... especially if it is already paid for, ... enjoy!

    Freezer ? Can u put in Freezer so animals dont come ???

    1 reply

    I'm not entirely sure what you mean. I think you're asking if you can dehydrate in the freezer rather than outside. The answer is no. Freezing will not remove the moisture (which is what is being accomplished by placing these items in the sun). If putting them in a sunny window or outside is a problem I recommend using a stand-alone dehydrator or using your oven as mentioned in the tutorial.

    Great 'bible' well done :) I've personally been using coffee grounds and banana skins as plant food for decades. Both are an excellent slow release food if you lay them on the surface of pot plants. Egg shells (lightly crushed) are also a fantastic slug/snail deterrent as well as a slow release food if crumbled up on the surface around plants. I then have my standard composters into which paper, cardboard, tea bags and veg peelings go.

    A good source of coffee grounds is your local Starbucks coffee shop. Certainly in the UK they bag the used grounds and offer it free to anybody who wants it and I don't think you have to buy a coffee from them :)

    1 reply

    That should of course say "great 'ible' :) Though, you could always start a composting/plant food making 'bible'. Again, well done.

    Good, clear, helpful InstructabIe. I think it's important to note, though, that this is not organic fertilizer unless the coffee, eggs, and bananas are organic.

    Also, you might want to correct a typo: bridle should be brittle ("

    You'll know they're dry when they're bridle and easily break apart.")

    1 reply

    Thank you. Spelling has never been my strong suit. I've made that correction. And yes, you're absolutely right about it only being as organic as the materials you're using. I had not thought on that as I was writing this. I get my eggs from my mother (farm chickens who are spoiled rotten! haha!) and buy as organic as I can with everything else. I will go back and make a note of that. Thanks for your input!

    I'm sure it does. For one, nothing has actually been decomposed, it's just dehydrated. In addition people typically put many other items in their compost, so considering that there would be many other elements from a compost soil. This is really made for people who maybe don't have a compost but would like a means of fertilizing their plants organically and on a budget.