A conveyor includes a frame, at least two arms at least one of which is movably mounted to the frame, at least two rails wherein each rail is coupled to an end of one of said at least two arms, at least two belts wherein each belt is rotatably mounted on one of said at least two rails such that the belts are capable of engaging plants therebetween and moving the plants along a conveyor axis, and one or more bias members which are configured to bias said at least one movable arm toward the other one of said at least two arms. The conveyor further comprises an expanding mechanism which is configured to exert an outward force on said at least one movable arm upon engagement so that said at least one movable arm move away from another arm.