Walipini Greenhouse: Year-Round Underground Greenhouse

Permaculture blog guide describing walipini as an underground greenhouse using earth insulation and passive solar heating, with Benson/Bolivia origin narrative, build outline, and FAQ on drainage, crops, and cold climates. Describes walipini as underground greenhouse utilising earth's natural insulation and passive solar heating for a stable year-round growing environment. States Walipini means 'place of warmth' in Aymara; places origin on high plains of Bolivia; credits Benson Agriculture and Food Institute 1990s development for local farmers. Mentions historical precedents: Victorian-era British pineapple pits; pre-revolutionary Russia underground citrus greenhouses. Typical excavation 6–8 feet (also states 2 / 2.5 m); transparent roof polyethylene or polycarbonate; oriented south-facing in the Northern Hemisphere.

Evidence tier: popular_guide. Permaculture/popular blog — not peer-reviewed research or primary Benson documentation.

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