DIY Greenhouse Underground

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The trench inside this greenhouse forms a heat sink during the day, while concrete block walls release heat at night.
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Greenhouses under 200-square-feet may require only four vents.

Dean Steward built a 14-by-24-foot “in-ground” DIY greenhouse for just $120. He simply trenched out a walkway between ground-level beds, walled it with concrete blocks and covered the beds with cattle panels and plastic.

Steward laid out his DIY greenhouse with two 24-by-4-foot beds separated by a 3-foot-wide trench and two waist-high block walls.

“I used a backhoe to dig out the trench and laid the walls without mortar,” says Steward. “I drove rebar into each cell and rammed earth in to fill them. It has been more than a year, and they are holding well.”

He added concrete block steps at one end and built end-walls out of scrap lumber. For the roof, Steward drove in two lines of wood stakes, 10 to a side and 12 feet apart. He fastened 16-foot-long, 50-inch-wide cattle panels between the stakes and covered them with plastic.

“I’m 5 feet 8 inches tall, but with the curve of the cattle panels, I can walk on the beds without hitting my head,” he says.

The trench forms a heat sink during the day, and the concrete block walls soak up heat to release as outside temperatures cool.

For more information on this innovative design, send Dean an email at

Reprinted with permission fromFARM SHOW Magazine.