Since houseplants live in a controlled, indoor environment, you need to fertilize them occasionally; this gives them the nutrients they would normally get from the soil if they were growing in the wild. While it is okay to use chemical fertilizers, natural fertilizers come closest to the way the plant would feed in its native environment. There are a number of ways to fertilize your houseplant using natural, organic materials.
According to the Compost Guide website, compost is the best plant food you can provide. Decomposing organic material in the compost feeds microorganisms that produce nitrogen, phosphorus and potassium. These keep the soil well-balanced and allow the plant to get the nutrition it needs grow and stay healthy. Compost also helps the soil retain necessary water, makes it more fertile and helps the roots to develop.
A successful compost pile will have a good mix of materials. Green material includes weeds, grass clippings, garden prunings and fresh leaves. Brown material includes dried leaves and flowers, wood chips, dead straw or hay. Kitchen waste items, such as vegetable scraps, potato peels, crushed or ground eggshells, tea bags, apple cores, fruit skins and wilted salad, are all beneficial to the compost pile. While meat and dairy refuse will decompose, it will create a strong smell that can attract insects, so it is not recommended. You can also add pine needles, wood ash and manure from vegetarian animals.
Small amounts of compost can be gently worked into your houseplants' soil or can be added to the soil when planting or re-potting.
An easier way to add fertilizer to a houseplant is through compost tea. A compost tea is a liquid fertilizer made by soaking compost in water overnight, then straining the solids out and saving the liquid. Add this liquid directly to you houseplants once or twice a month. By doing this the nutrients and microorganisms in the compost are transferred into the water. When you use the compost tea on your plant the organisms soak into the soil naturally and encourage plant growth. Using this method will not burn your plant.
Mycor Root Builders
Mycorrhizal fungi live on plant roots. They help the plant process organic chemicals in the soil and allow the plant to absorb and use these chemicals more efficiently. Mycor root builders are organic commercial products that contain materials such as endomycorrhiza, ectomycorrhiza, scleroderma, kelp, zeolite and humate. These products stimulates the mycorrhizal fungi on your plants, helping them grow and become more effective.
Bat guano (or feces) is an ideal fertilizer for most plants and has been used in horticulture for thousands of years. It is completely organic, high in phosphorus and promotes strong root growth. You can find bat guano products at most larger nurseries and greenhouses.
Commercial Organic Fertilizers
You can purchase a number of commercially prepared organic fertilizers. These include products made from a wide variety of materials such as enzymatically digested fish protein, seaweed extracts, feather meal, steamed bone meal, sulfate of potash, nitrogen supplements, microbial supplements and ground organic plant matter.
Common Household Items
Cooled coffee grounds, ground up eggshells, used tea leaves, bonemeal, cornmeal and wood ash, or any mixture of these, are good additions to your houseplant's soil. experiment and see what works best on your plants.
Never use dog or cat feces in your compost. Domestic animal waste can contain harmful parasites that will spread through their eggs. These eggs can live in soil for up to ten years and can transfer to humans on the fingers.
Even if you have a bat house or two in your back yard, never try to harvest your own bat guano for fertilizer. It can be toxic if not handled and processed properly.
Be careful when adding compost or other fertilizers to your plants. While fertilizer is good, too much of it can cause a healthy plant to become sick.