The word “Hugelkultur” describes an Eastern European method for building garden beds that is seeing renewed popularity. Beds are constructed by piling alternating layers of logs, branches, and soil. Then the bed is topped with soil. Hardwoods, aspen, cottonwood or fruit wood work best. Avoid using wood from black walnut, locust, pine, or juniper because these trees give off naturally produced chemicals, or antimicrobial agents, which might kill or slow down plant growth.