Alternatives to Commercial Fertilizers

Commercial chemical fertilizers give plants a large amount of nutrients in a concentrated, convenient form. However, they contain chemicals and "inert" ingredients that have been questioned for their negative effects on the environment as well as on human health, according to the book "Fateful Harvest." Natural fertilizers are available for purchase, and you can also make your own by starting a compost pile or a worm bin.

Fish Emulsion

This product, which is derived from waste from the fish food industry, is a time-honored natural fertilizer for all types of plants. It contains four parts of nitrogen, one part phosphorus and one part potassium, along with sulfur and other trace elements. Fish emulsion is sold as a liquid. You mix 1 tbsp. into one gallon of water, and either water your plants at their root zones or spray the plant's leaves. The fertilizer's release rate is fast, and is most effective when applied to your plants in early spring. The odor can be strong, so be sure to thoroughly water your plants with clear water after you fertilize them with fish emulsion.

Compost

Compost is nothing more than decomposed natural materials, such as chopped-up plants, kitchen scraps, fallen leaves and grass clippings. You can purchase bags of organic compost at your garden supply store, or you can easily make your own. Different types of containers are available for creating compost, or you can start a simple pile on the ground, alternating layers of fresh green plant materials, such as lawn clippings, and dry brown materials, such as fallen leaves. Compost often has a ratio of nitrogen, phosphorus and potassium (N-P-K) of .5-.27-.81, according to Allotment.org. Even though the nutrient ratio of compost may be less than that of commercial fertilizers, it has the advantage of adding humus to the soil, thus improving drainage and soil texture.

Animal Manures

Farmers have long used the manure from cows, horses, pigs, chickens, sheep and rabbits to nourish their crops. The N-P-K ratios of animal manures are typically balanced among the nitrogen, phosphorus and potassium readings. For example, horse manure measures an N-P-K ratio of .7-.3-.6. You can purchase many types of manure at your garden supply store, or you can gather your own. Always be sure to compost raw animal manure well before you apply it to the root zones of plants because it is strong stuff and can burn your plants. You can also make manure tea by adding about 1 quart of manure to 5 gallons of water. Stir it, let it sit for no longer than 24 hours, and then water your plants with this nutrient-rich mixture.

Natural Fertilizers From Animals

For a strong boost of nitrogen, which will promote the growth of foliage, choose hoof and horn meal or bloodmeal, with N-P-K ratios of 12-0-0. Bonemeal is recommended for flowering bulbs, with its N-P-K ratio of 3.5-18-0. A combination of fish, blood and bonemeal contains a balanced N-P-K ratio of 6-6-6. All of these natural products are available for sale at garden supply stores in a dry, granular form; the package label will include instructions on how to mix the product with water and apply it.

Worm Castings

Red wiggler worms make rich manure called "castings," which serve as a good plant nutrient, with their N-P-K ratio of 3.2-1.1-1.5. Worm castings are sold at retail stores, but these may be diluted with ingredients such as potting soil or compost, according to Carolina Organic Depot. Worm castings also contain trace elements and micronutrients, natural enzymes and good bacteria, that help reduce the need for pesticides and fungicides. You can start a simple worm bin under your kitchen sink and deposit your food scraps in it for an odor-free, safe natural fertilizer.

Keywords: fertilizer natural, organic gardening, worm castings, fish emulsion, compost plants

About this Author

Barbara Fahs lives on Hawaii island, where she has created Hi'iaka's Healing Herb Garden. Fahs wrote "Super Simple Guide to Creating Hawaiian Gardens," and has been a professional writer since 1984. She contributes to Big Island Weekly, Ke Ola magazine, GardenGuides and eHow. She earned her B.A. at UCSB and her M.A. from San Jose State University.