Making plant food is simple and easy to do from simple items found around the house. These can be a much cheaper, chemical free and ecofriendly way of feeding your plants than the harsh synthetic fertilizers found in the garden-supply section.
Add one envelope of gelatin powder to 1 cup of boiling water. Gelatin can provide plants with needed nitrogen. Once the gelatin is completely dissolved add it to 3 cups of cold water. Mix well and pour onto plants.
Rinse the eggshells and place them in a water pitcher as you use them. Add water and let the eggshells soak in the water. Use the mixture to water plants. Keep adding shells and water plants as needed. Eggshell are a source of calcium.
Mix 1/4 cup of ammonia in a gallon of water for plants that thrive on alkaline soil. Place the mixture in a watering can and sprinkle it over the plants. This shouldn't be done often because it will become too alkaline for the plant. Another alternative for these types of plants is to sprinkle wood ashes from natural, chemical-free wood onto the soil in the spring time.
Sprinkle used coffee grounds around plants that thrive on acid. Coffee grounds have also been shown to inhibit fungal diseases on some vegetable crops including spinach, beans, cucumbers and tomatoes.