An all-purpose potting mix has composted bark, peat moss or peat humus added to loamy soil.
The end point of decomposition is a largely inert organic material called humus .
There is a smell of humus and dirt and leaves and rain and nothing else.
But (as some might reply) we can add peat or humus to the soil as we till.
Lack of biological insect control necessitates using more pesticides, as lack of humus and plant litter necessitates using more chemical fertilizers.
The final product, humus or compost, looks and feels like fertile garden soil.
The mulch keeps the soil moist, and as the lower layers decompose, they enrich the soil with humus .
Cabbages tolerate heavier soils well, so long as there is enough humus and fertiliser, as they are heavy feeders.
Since these species originated in a wooded habitat, they require a loose soil with sufficient humus .
If grown in plenty of humus and leaf mould, rhododendron roots almost peel off the ground.