This is one of the keys to a successful passive structure. In reality this is a pit greenhouse for the floor is in the original earth about two feet below the outside ground level. This also contributes to its success as the natural earth temperature below the freeze line is usually about 50 degrees. You can see in this photo that climbing plants also provide shade to other vegetables during the summer months. Vents are two thirds at floor level, one third higher up for heat outlet.
Water comes from their own on site well.
In fact many of the materials used in the Otero's construction are recycled. Typical vegetables grown every year include tomatoes, chilies, melons, lettuces, spinach, garlic and more. Flowers and herbs round out the selection, grown indoors and out per seasonal requirements. In addition to providing much of their own food for the table, they also offer much of their harvest for sale to the public via a local Farmer's Market, directly or through market and restaurant outlets in the region. They are an excellent source for organic seedlings, something not easy to find from commercial nurseries.