Abstract: A molded plant tray is provided in the form of a unitary molded plastic member formed of relatively light foamed plastic and having downwardly extending tapered plant cells for receiving planting medium in which individual seedlings are grown. The plant tray is provided with integral drive member receiving groove means in the form of U-shaped grooves along bottom portions of intermediate walls that define the plant cells. An alignment groove can also be provided perpendicular to the drive member receiving groove means and bisecting the length of the drive member receiving groove means for accurate positioning of the plant tray relative to drive members. In a second embodiment a relatively hard plastic insert is molded, manufactured or adhesively secured to create a dual body tray in the molded plastic member and defines the plant cells.

Abstract: A molded plant tray is provided in the form of a unitary molded plastic member formed of relatively light foamed plastic and having downwardly extending tapered plant cells for receiving plating medium in which individual seedlings are crown. The plastic member is provided with a plurality of parallel, U-shaped indexing rod-receiving grooves defined on the bottom surface of the plastic member by portions of the intermediate walls that define the plant cells. The indexing rod-receiving grooves are complementary in shape to a plurality of indexing rods arranged in parallel spaced relation in a drum shape rotatable about a longitudinal axis and spaced to receive the indexing rods as they rotate about the longitudinal axis. A U-shaped alignment member-receiving groove is also provided, and is defined on the bottom surface of the plastic member by portions of the intermediate walls to extend perpendicular to the central axes of the indexing rod-receiving grooves.

Abstract: A novel greenhouse curtain system has a plurality of movable curtains oriented vertically one above the other to form a flexible wall. Each curtain is supported by a fixed upper edge, and the vertical position of the lower extent of each curtain may be adjusted by means of a traveling spindle used to furl or unfurl the curtain. The traveling spindle rises and descends as the curtain is furled (raised) or unfurled (lowered), and is rotated by a tensioned cable wrapped in opposite directions around two drums aligned concentrically one on end of the roller bar. The cable is anchored on one end below one of the drums, and is wrapped in opposite manner respectively around both drums and passes vertically to a pulley, and then to a driving means such as a winch. The dimensions of the drums are such that the curtain remains in stable position as long as there is no movement of the cable to or from the driving means.