In general these soils are deficient in lime, magnesia, phosphates, nitrogen, humus and potash. Needs a compost containing plenty of humus and sufficient moisture in summer. It grows best in well-drained acidic soil of rich humus and small stones. The soil is rich in minerals and humus, thus conducive to agriculture. Many other species are found in habitats such as mossy, grassy, or forest humus soils. Some judge earthworm humus (vermicompost) to be the optimal organic manure. They are planted in soil rich in humus and well drained. Potassium deficiency can also occur in sandy soil which has less humus. The best growth is reached on fertile soils rich in humus. The majority of fungal biomass is found in the humus and litter layers of soil. In alpine areas podzolic, humus and leached soil is most common. The soil should be humus and systematically watered. This suggests an ambiguous boundary between humus and soil organic matter. Various additives may be included, such as humus or compost. Larvae play an important role in formation and accumulation of humus in soil.