Whitcomb, Carl E.; Board of Regents for the Oklahoma Agriculture and Mechanical Colleges Acting for an in Behalf of Oklahoma State University (U.S. Patent and Trademark Office, 1985-04-16)
A vertical air-root-pruning container involving a series of vertical air gaps displaced around the sidewall of a container. The air gaps are alternately displaced outwardly or inwardly to air-prune spiral root growth in ...