Source link : https://las-vegas-news.com/soil-batteries-keep-figs-growing-through-pennsylvania-winters/
Pennsylvania greenhouse stays warm by storing heat underground – Image for illustrative purposes only (Image credits: Pexels)
Tim Clymer wanted to grow subtropical fruit in south-central Pennsylvania without relying on propane heaters that burn through hundreds of gallons each winter. At Threefold Farm, he turned the ground beneath a high tunnel into a storage system that captures daytime warmth and releases it at night. The result lets citrus and figs survive the cold months on electricity alone.
How the underground system captures and releases heat
On sunny days the greenhouse air warms naturally. Fans push that moist, heated air through a network of perforated pipes buried two to eight feet deep. The air transfers its heat to the surrounding soil and condenses, leaving cooler, drier air to return to the structure. At night or on cloudy days the fans reverse direction, pulling stored warmth back into the growing space. Three separate battery zones sit under the 30-by-96-foot tunnel. Each zone uses long runs of four-inch tubing connected to larger manifolds. The design keeps the top two feet of soil free for planting while still tapping deeper earth heat when temperatures drop. Total tubing length exceeds four thousand feet, yet the entire fan array draws only about eleven hundred watts.
Plants that now thrive year-round
The setup protects in-ground fig trees and allows overwintering of Meyer lemons and satsuma mandarins. These subtropical crops would normally…
—-
Author : Matthias Binder
Publish date : 2026-05-18 14:18:00
Copyright for syndicated content belongs to the linked Source.
—-
1 – 2 – 3 – 4 – 5 – 6 – 7 – 8