Our current cold frame specifications:

• The total outside dimensions are 96" x 42" x 41" high.
• Three chambers each measure approximately 25" x 32" in area. The right hand one has no window glazing.
• Walls are 3/4" marine grade plywood with 3.5" of fiberglass insulation between inside and outside walls, for a total thickness of 5"
• Double-glazed lexan window panes are Macrolux 8mm twin wall clear polycabronate, which is UV stabilized.
• Automatic vents (Bayliss Triple Spring MK7 Vent Opener ) open the left and center chambers if it gets too hot.
• Temperature and humidity data loggers (MicroDAQ LogTag) record in all three chambers. So do min-max recording thermometers.
• Soil depth is approximately 12". We used E. B. Stone organic "Edna's Best" potting soil.
• Hardware cloth is used on the bottom and sides and top to deter rodents.
• A gravity-fed drip irrigation system with a 75 gallon reservoir waters all three chambers.
• An electrical system using an 80-Watt Sharp photovoltaic panel, a 12-volt sealed battery and a digital timer was added in 2010 to power a water pump and other electrical devices.