From early-season start production to enjoying winter tomatoes, we are blessed to have the use of a year-round greenhouse.  The design of the greenhouse has multiple strategies at play to increase productivity twelve months of the year.  The GH is sighted 4’ below grade, which allows for the thermal mass of the earth to moderate temperature fluctuations, thereby taking the chill off January days.  The floor of the GH sits above 7’ of clean aggregate which is entwined with 3000’ linear feet of perforated drain pipe.  The pipe is connected to several fan units that monitor the internal temp of the GH.  When temperatures get too hot, the fans kick on and suck the hot air down into the aggregate below, while cold air is brought into the space.  Conversely, when temps drop at night getting too cold, the fans kick on again and bring the warm air into the space which was captured earlier in the day.  It is a daily revolving process of air-exchange bringing hot or cold air into the space to keep the GH at optimum growing capacity.  Should daytime temps get too hot for the fan system to moderate, there is a roof mounting exhaust fan which will run per its setting to assist in keeping temps as desired… when this runs, cold air is drawn up and through cold tubes placed 7’ deep adjacent to the building.  Though all sounding somewhat complex, simple electrical fans at minimum electrical loads efficiently monitor and control the desired temps for year-round production.