An apparatus and method for providing a simpler and more robust mechanism for transporting materials to be dried through a vacuum microwave chamber in rotating containers. The apparatus (20) has a vacuum chamber (22), an input end (26) to introduce a container (24) into the chamber, and a discharge end (28) to remove the container. The container has spur gear teeth (60) extending along its outer circumferential surface. The apparatus has a single roller (42) having spur gear teeth (46) extending along its outer circumferential surface. The spur gear teeth of the roller mesh with the spur gear teeth of the container such that rotation of the roller about its longitudinal axis rotates the container. The apparatus also includes means for holding the container on the roller, means for moving the container through the chamber, a microwave generator 76 arranged for transmission of microwave radiation from the generator into the chamber, and means for reducing pressure inside the chamber.

A method of drying hemp plants using a rotary drying system that dries the plants without damaging the cannabidiol in the plants.