Mature compost is the best fertilizer for the garden – and a natural and free one at that. But to convert organic waste into useful substrate, the compost heap in your garden must be open at the bottom.
Only then can earthworms and other invertebrates enter and promote the rotting process. The German Renewable Resources Agency (FNR) therefore advises against using containers that are closed at the bottom or covering the ground with stone slabs. A location in partial shade is also a good idea.
The right mix
The agency recommends shredding larger waste before adding it to the compost heap. In addition, household and garden waste decomposes best when the components are alternated. A layer of dry tree or hedge cuttings should be followed by moist plant or kitchen waste. Freshly cut grass should ideally be mixed with shredded branches.
By alternating the materials, the compost inside heats up to about 60 degrees Celsius and digests the green waste, killing harmful organisms.
Turn and sift twice a year
In between, however, the layers must be turned so that the microorganisms in the mixture get fresh air and the decomposition process continues. The FNR experts advise turning the heap twice a year – ideally in spring and autumn, when trees and hedges are pruned and there is a particularly large amount of new green cuttings to mix.
When turning the pile, the material already on the compost should be passed through a sieve – what comes out at the bottom is ready for the garden. Anything that is still too big goes back into the composter. The coarsest material goes to the bottom, followed by dry and moist layers alternating with smaller material.
The more often you turn the pile, the faster the composting will happen, experts say.
