Organic fertilizers are naturally-occurring fertilizers (e.g. peat moss or green manure), or naturally occurring mineral deposits (e.g. saltpeter).
Naturally occurring organic fertilizers include manure, slurry, worm castings, peat, seaweed, humic acid, brassin and guano.
Processed organic fertilizers include compost, bloodmeal, bone meal, humic acid, amino acids, brassin and seaweed extracts.
Other examples are natural enzyme digested proteins, fish meal, and feather meal. Decomposing crop residue from prior years is another source of fertility.
Although the density of nutrients in organic material is comparatively modest, they have many advantages. The majority of nitrogen supplying organic fertilizers contain insoluble nitrogen and act as a slow-release fertilizer. By their nature, organic fertilizers increase physical and biological nutrient storage mechanisms in soils, mitigating risks of over-fertilization. Organic fertilizer nutrient content, solubility, and nutrient release rates are typically much lower than mineral (inorganic) fertilizers.
They re-emphasize the role of humus and other organic components of soil, which are believed to play several important roles:
* Mobilizing existing soil nutrients, so that good growth is achieved with lower nutrient densities while wasting less
* Releasing nutrients at a slower, more consistent rate, helping to avoid a boom-and-bust pattern
* Helping to retain soil moisture, reducing the stress due to temporary moisture stress
* Improving the soil structure
* Helping to prevent topsoil erosion
For more indoor,outdoor, and hydroponics information, please visit San Diego Hydroponics & Organics website.