Making your own organic plant food is easy and fun. It should be noted that most people understand that the best way to get good garden soil is to use compost to amend the soil. Of course, that is true. Compost can be made at home out of leftover food scraps and lawn clippings, and so it is virtually cost-free
Always remember the one basic rule that applies to the use of all fertilizers—”less is more.” If you use too much fertilizer or too strong a concentration, you could do much more harm than good. Plant roots can be harmed and you will soon see the tell-tale symptoms of fertilizer burn—brown, curled leaf edges and leaves that wither and fall from the stem. Always err on the side of caution—”less is more!”
Easy Household Fertilizers
There are quite a few common items found in your kitchen, and elsewhere around the house, that can be used as plant fertilizer.
Bananas
Bananas are not only tasty and healthy for humans, but they also benefit many different plants. When planting roses, bury a banana (or just the peel) in the hole alongside the rose. As the rose grows, bury bananas or banana peels into the top layer of the soil. Both of these approaches will provide the much needed potassium that plants need for proper growth.
Coffee Grounds
Used coffee grounds contain about two percent nitrogen, about a third of a percent of phosphoric acid, and varying amounts of potash (generally less than one percent). Coffee grounds are particularly useful on those plants that like things a bit more acidic such as blueberries, evergreens, azaleas, roses, camellias, avocados, and many fruit trees. I recommend that you allow the coffee grounds to dry and then scatter them lightly, as a mulch, around your plants. Avoid scattering them thickly when they are wet, because clumps of coffee grounds have a tendency to get moldy.
Cooking Water
Many different nutrients are released into the water that food is cooked in. Water that is used to boil potatoes, vegetables, eggs, and even pasta can be used as a fertilizer. Just remember to let the water cool before applying it to your soil.
Egg Shells
Egg shells contain about 1% nitrogen, about a half-percent phosphoric acid, and other trace elements that make them a practical fertilizer. Calcium is an essential plant nutrient which plays a fundamental part in cell manufacture and growth. Most roots must have some calcium at the growing tips to grow effectively. Plant growth removes large quantities of calcium from the soil, and calcium must be replenished, so this is an ideal way to “recycle” your egg shells. Simply crush them, powder them in an old coffee grinder, and sprinkle them around your garden soil.
Gelatin
Gelatin can be a great nitrogen source. Dissolve one package of gelatin in 1 cup of hot water and then add 3 cups of cold water. Pour directly on the soil around your plants once a month. This is great for houseplants!
