Low tunnels are made by placing plastic or fabric row covers over wire or plastic hoops and securing with clips, to lengthen the growing season for the crop and improve overall crop health and quality. Vent holes or slits allow for adequate air circulation and ventilation during warm temperatures. Low tunnels usually have a peak height of 18” to 36” from the soil surface. Sometimes called a cloche.
Low Tunnel Ventilation Introduces the importance of monitoring temperatures in low tunnels and describes several ventilation techniques. University of Kentucky Extension.
Season Extension Techniques Season extension can enable year-round crop production as well as higher-quality produce. This publication describes season extension techniques and provides sources for equipment, supplies, and further information. ATTRA.