For off-grid, year-round veggies--even in sub-zero temps--get to building a "forever green" geo-thermal hoophouse!
Read nearly everything you'd ever want to know about pit greenhouses and see multiple examples, here:
Build an Underground Year-Round Greenhouse for Only $300 — And Grow Food All Year Long
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Walipini : Underground greenhouse More
A walipini / underground greenhouse is a great way to extend growing seasons, especially in cooler climates!
How To Build an Underground Greenhouse — Growing your own food isn't difficult in the summer, but winter gardening is a lot more complicated. It is made infinitely easier when you have a space that is insulated from the elements.
Walipini Greenhouse Plans | The outside of the greenhouse provides for a a lot of new growing ...
Build an underground greenhouse for year ‘round vegetables (Photos) - Atlanta Holistic Health | Examiner.com
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