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  • Writer's pictureMarie Katherine

The BEST DIY Indoor Plant Fertilizer (from Kitchen Scraps)

Updated: Sep 7, 2023

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There are many many DIYs for homemade indoor plant fertilizer, but unfortunately, most of them do not contain all the nutrients that a plant needs!

Indoor plants require these THREE nutrients to thrive: nitrogen, phosphorus, and potassium.

Plants also thrive with magnesium, calcium, and other trace minerals, but they absolutely MUST have nitrogen, phosphorus, and potassium to survive.

Store-bought potting soil will most likely contain these nutrients, but after some time, the plant will have used up the nutrients in the soil and require more. Ideally, plants need to be fertilized every 2-4 months.

Sure, you can purchase fertilizer, but WHY when you can make your own at home with food scraps from your kitchen?

Here is my recipe for the BEST DIY Indoor Plant Fertilizer:

2-3 Banana peels

Just like the fruit that we eat, the peel is full of potassium, which plants must have to survive! Banana peels also contain trace amounts of magnesium, sulfur, and calcium, which a house plant will also benefit from.

Use organic bananas, if that’s an option for you, as this prevents unwanted chemicals such as pesticides in your fertilizer.

1 cup of bone meal:

Bone mill is an unusual ingredient, but is SO good for houseplants. Plants thrive off animal waste or animal products (think of how the Native Americans added a dead fish in the hole when they planted corn. Or of how most compost purchased for a vegetable garden is some form of animal manure). That’s because these animal products contain high amounts of phosphorus!

Phosphorus can be difficult to get from other ingredients. Many people use egg shells for phosphorus, but egg shells are only made up of 3% phosphorus. Another common ingredient is wood ash, which actually only contains 2% phosphorus and is considered a “low-grade” fertilizer. These ingredients can be subbed though if you really don't want to use bone meal. However, bone meal contains 15% phosphorus, which is a much higher concentration. The other possible fertilizer options high in phosphorus are manure or fish emulsion, so bone meal is a preferable option for indoor plants.

I recommended getting bone meal from making your own bone broth. Here’s my recipe. Bone broth is excellent for health, and reduces food waste! If the broth is cooked for an appropriate amount of time, the bones should be easily crushed with a wooden spoon. (Chicken bones take less time cooking to crush). Crush the bones very finely, and take about a cup to add to your fertilizer. You can also purchase a bone meal here.

½ cup of used coffee grounds:

Coffee grounds are high in nitrogen, which is the third and final necessary nutrient in a good fertilizer! Make sure you use “used” coffee grounds so that you don’t just make a cold brew. Coffee grounds also contain potassium, magnesium, calcium, and other trace minerals, which are all excellent for plant health!

Try and use organic coffee, to again, avoid unwanted pesticides in your fertilizer.

Add all of these ingredients into a gallon jug or jar, seal, and let brew for 2-3 days. Remove the banana peels, and you’re ready to go! As you water your plants, be sure to aggregate the water with a spoon so that each house plant gets a little coffee grounds and bone meal.


And that's it! The BEST DIY indoor plant fertilizer! This recipe is the best because it incorporates all the nutrients that houseplants need to thrive!

Want to learn more about plant care? I write a LOT about gardening! Check out my posts on homesteading! I write about topics such as amending poor soil conditions and setting up a rainwater collection system!

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