Synthetic soil fertilisers contain nitrogen, potassium and phosphorous in pure forms to swiftly deliver needed nutrients to growing plants. Organic fertilisers consist of plant and animal matter that decomposes slowly, which provides plants with a longer-lasting supply of nutrition. While commercial preparations of organic fertilisers may be purchased at garden supply stores, they're often expensive. Cost-conscious gardeners can make their own organic fertiliser simply by combining a few ingredients together.
Making Homemade Fertilizer
The primary component of homemade organic fertiliser is seed meal, a vegetable oil byproduct that is used to feed livestock. Seed meal, which comes from sunflowers, soybeans, cottonseed and flaxseed, can provide plants with the same nitrogen, potassium and phosphorous found in commercial fertilisers. For a cheap and readily available alternative to seed meal, substitute grass clippings. Powdered limestone, known simply as lime, adds calcium to homemade fertiliser. Three common varieties of lime -- agricultural lime, dolomitic lime and gypsum -- may be added in any combination to the fertiliser recipe. Bone meal and kelp meal are optional additions that supply plant-friendly nutrients. Bone meal, made from coarsely-ground animal bones, provides an additional source of phosphorous, while kelp meal, made from dried seaweed, provides a wide variety of minerals that encourage healthy plant growth. These fertiliser ingredients may be purchased online and at gardening centres and farm supply stores. Buying in bulk quantities is the most cost-effective option. To make fertiliser, combine four parts seed meal with one part lime, one part bone meal and one part kelp meal. Measure the ingredients by volume, not weight. A large plastic bucket makes a good container in which to mix and store the fertiliser. As organic fertiliser is less potent than synthetic fertiliser, you will have to use more in the garden to achieve the same results.
A nutrient-rich liquid fertiliser can give plants an additional boost. Any form of manure, except for the parasite-ridden manure of dogs and cats, may be used to make liquid fertiliser; however, nitrogen-rich chicken manure works particularly well. Combine manure with an equal amount of water and let the mixture brew for at least a week. To use as a fertiliser, combine one part of the manure mixture with ten parts of water before spreading it across the garden. A manure-free liquid fertiliser option can be made by mixing weed clippings with an equal amount of water and letting it sit for a minimum of three weeks. This mixture should also be combined with ten parts of water before use.