What if you could turn your kitchen scraps into powerful plant food — with zero chemicals and zero cost?
With the right approach, common food waste like vegetable peels, rice water, banana skins, and coffee grounds can be fermented or soaked to create a nutrient-rich liquid spray. This DIY solution feeds your plants naturally, boosts growth, and improves soil life — all while cutting down on waste.
Let’s explore how to make this eco-friendly fertilizer spray that’s good for your plants and the planet.
Why Use Food Waste as Fertilizer?
Food waste contains valuable nutrients that plants love. When broken down and transformed into a spray, it becomes a gentle, bioavailable fertilizer that:
- Supplies macronutrients (like nitrogen, potassium, and phosphorus)
- Enriches soil with microbial life
- Improves leaf health and root development
- Helps reduce landfill waste
Instead of throwing scraps away, you’re recycling them into something your garden thrives on.
Best Food Scraps for DIY Fertilizer Spray
These kitchen items work exceptionally well:
- Banana peels – high in potassium and phosphorus
- Vegetable scraps – good overall nutrition
- Rice water – promotes root development
- Coffee grounds – adds nitrogen and organic matter
- Eggshells – rich in calcium
- Onion or garlic skins – trace minerals + pest resistance
- Fruit scraps – enzymes and micronutrients (avoid citrus for sensitive plants)
You can combine several or stick to a few depending on availability.
Ingredients & Supplies
- 1 cup chopped food scraps (mix of banana peel, veggie peels, rice water, etc.)
- 1 tablespoon brown sugar or jaggery (for fermentation)
- 3 cups dechlorinated water
- Optional: ½ tsp Epsom salt or 1 tsp molasses
- Blender or jar
- Strainer
- Spray bottle
How to Make DIY Fertilizer Spray
🧪 Quick Fermentation Method (7 Days)
- Add the chopped food scraps to a clean jar
- Add sugar and water, then stir well
- Cover loosely with a cloth or lid with holes (gases must escape)
- Let ferment at room temperature for 5–7 days, stirring daily
- Strain the liquid and pour into a spray bottle
- Dilute 1:5 with water before spraying
🧃 Instant-Boil Method (Faster, Shorter Shelf Life)
- Boil your scraps in water for 15–20 minutes
- Let cool, strain, and pour into a spray bottle
- Use within 2–3 days
- Optional: add a few drops of soap if applying to leaves
How to Use the Spray
- Foliar spray: Mist on top and bottom of leaves early morning or evening
- Soil drench: Pour at the base of plants every 7–10 days
- Use every 7 days during growing season
- Avoid spraying flowers or buds directly
This spray is gentle enough for frequent use but should not replace all other fertilizers.
Best Plants for This Spray
Great for:
- Tomatoes, peppers, eggplants
- Leafy greens like kale, lettuce, spinach
- Houseplants (pothos, monstera, ferns)
- Herbs like basil, mint, coriander
- Flowering plants (roses, marigolds, zinnias)
Avoid spraying succulents and cacti — they don’t need frequent feeding.
Tips for Best Results
- Always strain finely to avoid clogging spray nozzles
- Use dechlorinated water to protect beneficial microbes
- Shake well before each use
- Don’t store fermented liquid for more than 10 days
- Alternate with compost tea or banana peel spray for balanced nutrition
FAQs About Food Waste Fertilizer Spray
Will this smell bad?
A mild sour or earthy smell is normal. If it smells rotten or foul, discard it.
Can I use citrus peels?
Only in small amounts. Too much citrus can make the spray too acidic.
Is it safe for vegetables and fruits?
Yes! Just avoid spraying directly on parts you plan to harvest soon.
Can I add yeast to speed up fermentation?
Yes, a pinch of yeast can help—but it’s optional.
What if mold forms during fermentation?
White mold is fine. Black or slimy mold means it’s gone bad — start fresh.
Final Thoughts
This DIY fertilizer spray is a game-changer — low-cost, chemical-free, and incredibly effective. By turning your food scraps into a natural liquid fertilizer, you support your garden’s health while reducing your household waste.