Bulletin #1057, Skill and Knowledge Checklist for Greenhouse Growers (PDF) Greenhouse showing intensive production methods and diverse crops. Furnaces are at both ends of the greenhouse. Photo by Mark Hedrich. Developed by Extension Ornamental Horticulture Specialist, Matt Wallhead, University of Maine Cooperative Extension. For information about UMaine Extension programs and resources, visit extension.umaine.edu.Find more of our