The Most Efficient Greenhouse on Earth | $100 a year to heat in -40C with Sand Battery Thermal Mass

This greenhouse is the most efficient and well designed cold climate greenhouse that has ever been built! Patrick built and improved the Arkopia deep winter greenhouse design, adding a Sand Battery that is charged by Solar Evacuated Tubes, and some other awesome innovations. In Alberta, Canada gardening zone 3 (same as Arkopia in Saskatchewan) this greenhouse keeps tropical plants going all winter with only $100 in total annual heating costs (just for those few -40C special nights). His family grows bananas, oranges, grapefruits, peaches, figs, grapes, and all the tropical things all year long even in northern Canada's harsh winter. They grow directly into the ground, in raised beds, and even did an awesome aquaponics set up using a massive 1000 gallon fish tank (thermal mass) where they grow some monster rainbow trout. A huge bird house awakens the indoor garden with symphony of songs, which is very good for plants (and humans). From all knowledge of greenhouse builds, this cold climate greenhouse currently is the best designed and functioning greenhouse on earth.