For successful organic gardening, the compost used should not only supply plant nutrients, but also should provide humus, which can remain active in soil for long time, thus favourably affecting soil biological and physico-chemical properties. Humus is formed from lignin (a hard-to-decompose polymer from old and hard tissues of plants) by the action of soil microorganisms. By adding organic wastes such as saw dust, wood shavings, coir pith, pine needles, dry fallen leaves etc. while preparing organic wastes mixture for composting, one can ensure that the compost produced would contain sufficient and long-lasting humus. But the usual experience of gardeners is that when lignin-rich plant materials are used, compost would not ripen fast. Here is a technique to make a good compost from hard plant materials. Just mix lime at the rate of 5kg per 1000 kg waste material. Lime can be applied as dry powder or after mixing with sufficient quantity of water. Treatment with lime will definitely and immediately enhance the process of decomposition of hard materials. This is based on the fact that liming can enhance humification process in plant residues by enhancing microbial population and activity and by weakening lignin structure. It can also improve humus quality by changing the ratio of humic to fulvic acids. Liming has also been shown to decrease the amount of bitumens, which interferes with the decomposition process.

In the place of lime, powdered rock phosphate can also be used successfully at the rate of 20 kg per 1000 kg organic wastes. Rock phosphate contains lots of lime. Phosphates and micronutrients contained in rock phosphate will also make composts rich in plant nutrients.

This simple and successful technique of enhancing composting process by using lime or rock phosphate can also be adopted for composting pure saw dust or wood shavings for use as potting media.