My 72-ft X 32-Ft double poly greenhouse in cold snowy Colorado is located a 5440 ft. elevation. In ground large greenhouse trees: Cara Cara, Saint Teresa lemon, Dekopon, Ponkan mandarin, Sour Orange, Marsh Grapefruit, Pomegranate, Page mandarin, and Valentine Pummelo, plus many 13 gallon container citrus trees. On a 17 degree below zero day, during a cold winter day, it is great to go into a 80F warm greenhouse full of green vegetation. Summer 12 months a year.