It might look like chocolate cake but it's a picture of a healthy root system. Rhizosheath is the soil that clings to the roots of a plant. It consists of root hairs, exudates, soil aggregates, and microbes. The microbes feed off of the root's sugar and carbon exudates. The microbes release nutrients in exchange for food. Soil particles become bound to the roots from the microbial secretions forming soil aggregates. Nicely covered roots are a sign of a healthy microbe population. Clean, white roots show a lack of microorganisms.
Rhizosheaths help plants by reducing drought, making nitrogen, phosphorus, and other nutrients more available and can buffer the pH of the immediate area around the roots by as much as 2 units. You can help your plants have robust rhizosheaths by making sure their soil has an abundant microbe population.
The picture above is the roots of the pepper seedling that I pictured in the last newsletter. In 2020 when I took the picture, I didn't know what a rhizosheath was or why it was important. The more you know, the more you understand how the world works!