We operate a sunken greenhouse as a test bed for various systems. The greenhouse floor is 4′ below grade in the front, and buried up to the roof in along the north wall. We overdug the foundation down 9′ with 1′ of drain rock trenched out to daylight. Then layered back in a row of 4″ drainpipe every 1′ of dirt. This serves as a Ground Air Heat Transfer (GAHT) system. The air when it gets too cold or too hot, is pumped underground where the temperature stays at the yearly average temperature all the time. This helps moderate the temperature of the greenhouse, such that even in our occasional week of freezing temperatures, the air inside has never dropped below 40°F.
Along the back wall we have 2 rows of black barrels that collect and store rainwater off the greenhouse roof. In the summer months these barrels are shaded by the angle of the opaque roof from the sun and in the winter, the low-angle sunlight warms the barrels up. Yet another feature to help moderate the interior temperature.
Hydroponics
We run a dedicated hydroponics system that feeds us salad greens throughout the winter.
Duckponics
The media bed in the greenhouse is served by water from our duck pond, pumped up into the greenhouse and then gravity draining back into the pond
In-Ground Bed
We have an in-ground soil bed that maintains a few plants throughout the year. We also have several potted plants that exist either year-round in the greenhouse, or over winter there.
Seed Starting
The greenhouse provides an ideal location to get plants started for eventual planting into our garden beds
Surrounding Beds
The back slope of the greenhouse, as well as the east and west beds provide a number of other options for small areas to grow