Due to their enormous surface area of up to 300 m² per gram, plant charcoals provide an ideal habitat for all the countless soil organisms and microorganisms responsible for converting biomass into humus.

They serve as an excellent storage medium for water and all the nutrients that plants need for their growth.

Plant charcoal can absorb up to five times its own weight in water and nutrients.

It protects the soil from both drying out—reducing the need for watering—and from leaching, as the nutrients are stably stored in the numerous pores of the plant charcoal.

Plant charcoal binds large amounts of carbon dioxide (CO₂) and soil contaminants, preventing them from entering plants or groundwater.

Plant charcoal does not degrade—once incorporated into the soil, it remains unchanged, as evidenced by findings from the Amazon region. Studies have shown that plant charcoal also fulfills an important catalytic function:

Normally, the breakdown of organic matter in the soil produces relatively small molecules that largely evaporate or get washed away. In contrast, plant charcoal supports the transformation into stable macromolecules, which in the next step combine to form permanent humus. This process continues steadily and explains the self-sustaining and "regenerating" properties of chernozem, independent of fertilizer inputs.

Within the pores of plant charcoal, an especially intensive cation exchange takes place, which ensures significantly better nutrient availability and uptake by plants.

Root mycorrhizae, which preferentially colonize the plant charcoal, also contribute to this.

However, plant charcoal must always be "charged" with nutrients like a battery before application—either in the garden, e.g., in a pile compost, and/or at home in bokashi. If applied pure to the soil, it would absorb the existing nutrients like a sponge, thereby harming established or new plants. It's also important to note that potassium-rich wood ash is not a substitute for plant charcoal and should only be applied sparingly (maximum 3 liters per 10 m²) or added to compost.