DIY Greenhouse Built from Recycled Materials for Under $400

"I've never been an idle person," says Amy Moore. Beyond caring for a family of eight, harvesting and selling honey, and raising chickens and horses on her 8-acre Tennessee property, she recently built her own greenhouse using primarily recycled materials.

After acquiring 26 vintage oak casement windows for free from a glass cutter, Moore decided a greenhouse would extend the short Tennessee growing season and provide a meaningful family project. Using basic tools—a circular saw, jigsaw, and battery-powered drill—she spent about a month and less than $400 to erect an 8-by-8-foot greenhouse on her family's ridge.

Resources abound for salvage projects—people discard building materials constantly, and many stores specialize in vintage and reclaimed materials. Moore's resourcefulness traces back to childhood summers at her grandfather's Texas lake house, where they'd hunt for building materials and "trash" others had tossed when "Granny needed a bigger closet for canning."

Constructing the Greenhouse

Moore's husband helped install 4-foot rebar pieces into a railroad timber foundation. Moore attached 2-by-4 framing for the walls. She involved her three youngest children (ages 10, 12, and 15) extensively—cutting roof panels, painting, and framing—wanting them to get hands-on experience before adulthood.

Two weeks later, the walls were up. The windows strongly influenced the framing design. Moore framed unconventionally to accommodate the maximum 27-by-42-inch window span. "Solid 2-by-4 horizontal beams between each row of windows give strength and stability," she explains. "The weight load is carried by horizontal beams and vertical 2-by-4 jack studs, while accommodating the existing oak frames."

Moore squared and plumbed the structure as she built, using decking screws that won't back out with seasonal wood movement. Her property's southeast ridge location offers shelter from most direct winds, though 70-foot-tall trees pose a potential risk.

The project wasn't without challenges. "I'm not a professional builder," Moore admits. Maneuvering a 6-foot ladder on an 8-foot wall and cutting rafters to fit flush tested her. "I'd take a glass of wine, walk down the hill, stare at the greenhouse, and ponder... If I can pack six kids in a van for a family trip, find room for luggage, and still access the cooler, I can make a rafter fit flush."

Two weeks after walls were up, a corrugated polycarbonate panel roof was installed. A pitched roof was originally envisioned, but this shed design involved less cutting and fewer panels (at $30 each). It keeps the rain out, though longevity remains to be seen.

Heating Strategy

Winter temperatures drop into the teens. Moore plans to use passive heating, observing temperatures over winter to determine if supplemental heat (perhaps solar panels) is needed. Maintaining 65°F over winter would make a world of difference.

She caulked the windows and let the kids paint with olive green. A transom above the door will control air and heat flow, and silicone caulking will tighten joints. "This greenhouse is going to be forever," Moore says.

Planting Plans

Pomegranates are a must—her grandfather grew them with Shasta daisies in Texas, bringing the process full circle. Avocados are on the wish list. She's considering salvaged stainless steel restaurant shelving for plant display. For now, two hanging planters and heirloom tomato cuttings are testing conditions while temperatures and sun patterns are monitored.

"It's perfect," Moore says. "Quiet but not removed. You can just sit there and watch the trees, the horses, and enjoy the house."

Materials List

• Foundation: Salvaged railroad timbers and 4-foot rebar pieces
• Framing: Various lengths of 2-by-4s; various-size lumber for trim, door frame, and base
• Walls: 26 oak-framed windows of various sizes; exterior latex caulk, primer, and paint
• Rafters: Seven 10-foot lengths of 2-by-6s, stained and sealed
• Roofing: Polycarbonate panels with fasteners and foam inserts
• Window ledges: Scrap 1-by-8 oak shelves
• Deck screws (2 inch, 2.5 inch, 3 inch)
• Door hinges (smaller for side windows, larger for door)
• Antique wood door
• Decorative door header: Scrap plate rail