How to Build a Pressure-Treated Wood-Framed Greenhouse

Lay two 72-inch boards parallel with their outside edges 96 inches apart. Set two 96-inch boards on top of them at right angles so their outside edges are flush with the ends of the 72-inch boards. Screw the 96-inch boards to the 72-inch boards using six screws for each board. This is one side to the green house. Repeat this step to build the other side.

Position the two sides upright and parallel, so the 72-inch boards are perpendicular to the ground. Space the sides so the outside edges of the 72-inch boards are 96 inches apart. Screw a pair of 96-inch boards to the 72-inch boards just like you did in the last step so you have four similar sides to your greenhouse frame.

Cut the ends of each 61-inch board at a 45-degree angle. The board will look like a trapezoid when lying flat on its longest side.

Lay a pair of 61-inch boards flat on their shortest side. Space them so they are parallel and 85 inches apart. Lay two 96-inch boards on top of them so their outside edges are flush with the ends of the 61-inch boards. Screw the 96-inch boards to the 61-inch boards. This is the door to your greenhouse.

Hold the door against a pair of 72-inch boards so the 61-inch boards are flat against them and flush with their sides. Screw two half-hinges to the top edges of the 96-inch board on the door so they are 12 inches away from the end of the board. Screw the other half-hinges to the 96-inch board that is directly above it so the door can open up and out from the greenhouse frame.

Lay the 120-inch plastic sheet over the top of the frame so the sheet edges are 12 inches away from each top 96-inch board. Fold the plastic sheet over the board and staple it to the board using a staple every 4 inches.

Position a plastic sheet against each side of the frame so there is 12 inches of excess sheeting along each side. This is the same method used in the last step. Staple the sheet to the frame and to the door just as you did in the last step.