How to Build a Small Portable Greenhouse

Gardeners can't wait to start seeds or grow new plants in the spring, but the weather may not always cooperate. Build a small portable greenhouse that can be moved around your garden to give maximum warmth and growing help to tender new plants. Easily built with simple materials, this greenhouse will extend your growing season.

Six-foot long rebar

1 inch flexible PVC pipe

Clear plastic or poly sheet

Glue-backed Velcro tabs or strips

Strong cord or rope

Tent stakes or similar

Clear waterproof tape

Sheers or strong scissor

Ladder

Measuring tape

Hammer

Bubble level

Measure the location you wish to place the portable greenhouse and mark the edges of the rectangular area. This is usually done over a garden bed or in a sunny corner of your yard where you wish to start seedlings for later transplant. Measure 3-foot distances down each long side and put a rock or other marker in that location. The supports for the portable greenhouse should be 3 feet apart for maximum stability.

Hammer a 6-foot piece of rebar into each spot marked with a rock from step one. Be sure the rebar is sticking straight in the ground and not tipped in any direction. Use a bubble level bar to check. The rebar should be stuck in the ground at least 3 feet so they do not shift. Putting a block of wood on the top of the rebar can help you hammer it in more easily.

Slip the ends of the 1-inch, flexible PVC pipe over each piece of rebar and bend them over the top of the portable greenhouse area to fit on the opposing piece of rebar. This creates the frame for your greenhouse.

Tie one end of the sturdy cord or rope to a long tent spike or similar apparatus that can be pounded into the ground. Measure the total width of the greenhouse frame area and find the center. Measure out 1 1/2 feet on either side of the center spot and mark that location with a rock. Use your hammer or mallet to pound the tied stake into the ground approximately 1 foot out from each rock marker. Do not put the stake in directly under the last PVC frame piece, as there will not be enough stability formed. Repeat this procedure for another stake and rope for the other rock marker.

Pull the rope up to the first PVC frame piece and tightly wrap it around the pipe, which must remain upright. Move along the entire row of PVC pipes, wrapping the cord around each in a similar way. Keep the rope tight. On the other end of the portable greenhouse frame, repeat the steps above to tie the rope to a tent stake and pound it into the ground. Repeat all steps with the second rope.

Pull the plastic or polyethylene sheet over the entire portable greenhouse frame so it lays smoothly over the PVC pipes. Use rocks, bricks or other even heavy boards to hold the edges down on the ground along each side. You may also use strong tape to attach the plastic sheeting to the PVC support pipes at the bottom. If you must use multiple pieces of the sheet, seal the seams with waterproof tape complete.

Cut a piece of plastic or polyethylene sheeting approximately 1 foot wider and taller than the end openings of the portable greenhouse. Cut this sheet in half down the center. Use waterproof tape to attach the top and sides completely to the piece of plastic stretched over the frame so that the cut edges overlap in the center. Attach Velcro tabs or strips to both sides of the overlapping flaps and seal it up. These can be opened and used as doors to get into the greenhouse, or used as vents to regulate temperature and moisture inside.