Plants need numerous elements to grow. Generally, all but 3 of these elements exist in the air and the soil in quantities sufficient to sustain plant growth. The other 3 elements, namely, nitrogen, phosphorous, and potassium are consumed by the plants in big quantities and, therefore, should be added to the soil in the form of fertilizers.
Organic fertilizers include animal and poultry manure, green manure, bone meal, granite dust, phosphate rock, and wood ashes.
1. Manure: Manure (cow, horse, pig, rabbit, chicken, etc.) is the main organic fertilizer. It is sold in different forms: raw, dehydrated, and composted. Raw manure is messy and smelly and, therefore, does not appeal to many gardeners. It also attracts flies and other insects. Furthermore, raw manure often contains a considerable amount of undigested weed seeds. These seeds germinate and grow weeds fast because they are in a nitrogen-rich environment. Controlling these weeds can be a difficult and time-consuming task.
