Ever wondered if you could skip the store-bought fertilizers and feed your plants with what’s already in your kitchen? Good news, you can! With just a few everyday ingredients, you can create natural, effective DIY plant food that keeps your houseplants healthy, happy, and thriving.
Let’s explore six easy (and affordable) DIY fertilizer ideas, plus a few insider tips on how to use them safely.
1.) Coffee Grounds
Why they work: Coffee grounds are packed with nitrogen, the nutrient plants need most for lush, green growth. They also add small amounts of potassium, calcium, and magnesium.
How to use: You can sprinkle used coffee grounds directly onto the soil, mix them into compost, or make a liquid “coffee tea” by steeping them in water overnight. For a deeper dive, check out our blog “What Indoor Plants Like Coffee Grounds?” for different ways to use coffee grounds on your houseplants and step-by-step how-tos guides.
Best for: Acid-loving plants like African violets, ferns, and ivies.
Wondering if you can use coffee grounds on all plants? Not quite, some plants prefer neutral soil, so it’s best to test on one plant first. “Coffee grounds lower the pH level of soil, causing it to become more acidic,” says Homes & Gardens. Gardening experts warn that overdoing it can make soil too acidic for certain plants, leading to brown leaf tips and damage.
2.) Eggshells
Why they work: A typical egg shell contains just over 2g of calcium, which makes up 95 per cent of the shell according to BBC Gardeners' World Magazine. Calcium is a must-have for strong cell walls and steady growth.
How to use: Rinse and crush the shells, then mix them into the soil or your compost. You can also steep them in water overnight to make a mild “eggshell tea.”
Best for: Succulents, cacti, and plants that like well-draining soil. Eggshells are not recommended for acid-loving plants, because they will make the soil more alkaline.
Curious if eggshells really help your succulents thrive? Yes! The slow calcium release can strengthen roots and prevent rot. Make sure to crush the shells finely for best absorption.
3.) Epsom Salt
Why they work: Epsom salt is rich in magnesium and sulfur, both essential for chlorophyll production and nutrient absorption.
How to use: Dissolve 1 tablespoon of Epsom salt in a gallon of water, then use it to water your plants once a month.
Best for: Plants showing magnesium deficiency (like yellowing leaves). Great for citrus plants, tomatoes, and peppers.
Quick Take: Not every plant needs Epsom salt. Use it only if your plant’s leaves look pale or yellow between the veins, a telltale sign of magnesium deficiency.
Wondering what the leaves of your plants are telling you when it comes to nutrient deficiencies? Learn more using the Royal Horticultural Society’s guide to common nutrient deficiencies and what your plants’ leaves are telling you.
4.) Banana Peels
Why they work: Banana peels are rich in potassium, which are essential for strong stems and vibrant blooms.
How to use: Cut peels into small pieces and bury them around the base of your plants, or blend with water to make a quick liquid fertilizer. Check out our guide to using banana water as a part of your plant-care routine.
Best for: Flowering houseplants such as orchids, bromeliads, and peace lilies.
Wondering if you can just toss banana peels in your plant’s pot? Not quite. It’s better to chop or blend them first. Whole peels decompose slowly and can attract fruit flies, annoying pests you don’t want to invite into your indoor garden.
5.) Fish Tank Water
Why it works: Used fish tank water is nutrient-rich (especially in nitrogen and phosphorus), exactly what plants crave for leafy growth.
How to use: Next time you change your aquarium water, save it and use it to water your plants. Just make sure it’s fresh (not salty or chemically treated).
Best for: Plants that love moisture, like ferns, calatheas (explore care guides for multiple calathea species in our Plant Guide), and mosses.
Bonus Tip: If you’re worried about a fishy smell using aquarium water— don’t! The scent quickly fades after watering.
6.) Seaweed
Why it works: Seaweed contains trace minerals like iron, zinc, and manganese. These are micronutrients your plants need for balanced growth.
How to use: If you live near the coast, you can collect seaweed at the beach. Just rinse seaweed thoroughly to remove salt, chop it up, and mix it into your soil or compost. Not by the ocean? You can also find dried seaweed in garden centers.
Best for: Humidity-loving plants like spider plants, philodendrons, and pothos.
Tips for Using DIY Fertilizer on Houseplants
While these DIY fertilizers can be effective for many houseplants, it's important to research and ensure they are safe for your specific plants. Some plants may be sensitive to certain ingredients or may require different types of nutrients. Always test a small amount of the fertilizer on your plants first and observe how they respond before using it regularly.
It's also crucial to remember that DIY fertilizers should be used in moderation. Over-fertilizing your houseplants can cause nutrient burn, or indoor plant soil salt-buildup which can harm your plants. Check out this blog on common fertilizer mistakes for more info!
How to Care for Your Houseplants (Besides Fertilizer)
DIY fertilizer is just one piece of the plant-care puzzle. To keep your plants truly thriving:
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Clean the leaves regularly to help them photosynthesize efficiently. Want to learn how to clean your plant’s leaves correctly? Check out this guide from The Spruce.
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Ensure proper light exposure. If your space lacks sunlight, grow lights are designed to mimic natural daylight. They’re especially perfect for winter months or low-light rooms.
Don’t know where to start when it comes to grow lights for your indoor plants? Learn how to choose the best indoor grow light for your plants on our blog.
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Repot when needed. Choose pots with drainage holes and the right size to match your plant’s growth.
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Prune regularly to encourage fuller growth and prevent overcrowding.
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Final Thoughts: DIY Plant Food
Creating your own plant fertilizer at home is a simple, sustainable way to support plant health without breaking the bank. With ingredients like coffee grounds, eggshells, Epsom salt, banana peels, fish tank water, and seaweed, you can nourish your plants naturally — while reducing waste in the process.
So next time you’re about to toss out your morning coffee grounds or eggshells, pause and think: Could my plants use this? Chances are, they’ll thank you for it.
Explore more plant care tips for your houseplants and how to help them thrive→ check out our Plant Guide!
