AN INENXPENSIVE GREENHOUSE VENT CONTROLLER
Plastics greenhouses do not lend themselves to natural air venting. A minimum of openings is desired for easy covering. Fans are normally used to draw air through the greenhouses. Intakes are normally motor operated louvers. This paper describes an inexpensive vent controller designed to open a side hinged vent in four steps through two 2-stage thermostats. Commercial greenhouse venting hardware is used in conjunction with the controller.
Roberts, W.J. (1975). AN INENXPENSIVE GREENHOUSE VENT CONTROLLER. Acta Hortic. 46, 55-62