The optimum scarification for planting is known as inverted humus. This provides the components that give plants the greatest chance of survival and the best growth potential.
Increased air and ground temperatures are attained because proper scarification creates a raised planting spot. Cold air is heavier than warm air and consequently the difference in temperature between ground level and a couple of decimeters above ground often measures a couple of degrees during the coldest part of the day. The fact that sunlight can more easily reach a raised and cleared surface also provides a higher temperature. The lack of vegetation allows heat loss during the night, providing a lower temperature in scarified areas on clear nights. The extra sunlight provides not only increased temperature, but even more energy for photosynthesis. Scarification increases nutrients because the humus layer is compressed and imbedded in the mineral soil. The nutrients in the humus and mineral soil must compost if they are to be made available to the plants, and an important factor in rapid composting is warmth. This determines the rate of decay and thereby nutrient availability.
The oxygen and water balances of the soil are also important aspects to consider when reducing the risk of the plant dying young and to optimize growth. A soil with well-balanced moisture content never feels wet or damp to the touch. Practical experience and extensive trials show that a considerably larger number of plants that die do so by drowning rather than drought. An optimum balance between water and oxygen in the soil means reducing the water content for the greater part of the growing season. This is done by scarification, which creates a higher planting spot than if the plant is planted at ground level. In this way, the soil is drained of water thereby eliminating the risk of the plant drowning. Draining the soil by scarification also creates a flow of rainwater that ensures the soil is oxygenated, which allows the plant’s root system to develop well. The right combination of oxygen and water also helps increase the rate of composting. Composting is slow, for example, in marshlands where the water content is high and on dry soil where the water content is low.