Saturday, December 27, 2008

Build an Easy 5 x 5 Greenhouse for under $25
See detailed step-by-step instructions at

Cold Frames & Greenhouses by The Pond Plant Girl
Gail M. Gates 11/08

A 4' x 6' greenhouse like this one can cost $329.00 or more! The best price I have found for a decent small greenhouse is at Harbor Freight and Tools online and costs $329 for a 4 x 6 foot Plexiglas and aluminum structure. This is actually an impressive greenhouse for the price. For those of you who live in snow country, this is the way to protect your winter plants. Heating a greenhouse such as this one is another challenge and will be covered in future articles. However, there are affordable options such as a hot wire to keep off the snow pack and a small pellet stove to keep the air temperature above freezing. In extreme cold climates, not all water garden plants can be wintered over in a greenhouse and a few will need to be brought indoors and placed in a bright window in a hydroponics container.

A 5' x 5' Cold Frame costs only = $20.50

If you live in zone 7-8 and above where the temperature rarely sees the freezing point, then a cold frame will support your pond plant needs well. The photo to the left was a cold frame that I constructed by myself in one day. This one is 10' long x 5' wide. The 3.5 mil thick plastic was attached with zip ties and came in a box at Home Depot containing a 25' long x 10' wide sheet. Be sure to slice small holes for rain drainage. If you live in a cold winter region, I would suggest using 6 mil thick plastic for your cold frame. This type of cold frame will not withstand a snow pack unless Plexiglas is used. I plan to construct a smaller 5' x 5' cold frame (with instructions below) for my kiddie pool pond.

What You Need for One 5' x 5' Cold Frame / Greenhouse

☼ 1/2" PVC Pipe

☼ 1/2" Corner Elbow Connectors

☼ 1/2" pvc Adapters
☼ Scissors
☼ Long Zip Ties
☼ Hack Saw or Pipe Cutter
☼ Visquene or Plastic Sheeting 6' x 6', 3.5 mil (6 mil is ideal) Thin clear plastic will not withstand past one season.

Putting it Together - Here's the good news! I was able to construct this cold frame all on my own and you can too! See Video

Assemble the pipe on a dry surface in a well ventilated area, such as a patio or driveway.

Cut 2 of the 10' sections of PVC pipe in half, making a total of 4 - 5' sections of pipe.

Swipe the inside of the elbow pieces and the ends of the PVC pipe with the purple primer. Do not swipe the inside of the threaded elbows.

After the primer dries, attach the elbows to the ends of the two 5' section of pipe with the PVC cement.

Attach the 10' section of pipe to the unthreaded end of an elbow with PVC cement and press down firmly.

After the cement will dries within a few minutes, carefully bend the 10' section of pipe and attached to the other unthreaded end of the 5' section of pipe with cement. Leverage might be needed to bend the pipe, such as leaning up against a wall to prevent slipping while bending the pipe.

Your basic end-piece shape should look like this!

Repeat steps 3-6 for the other end of your cold frame.

Lay down the cold frame end on the plastic sheeting and cut out the end piece to attach. Be sure to leave at least 6 inches overlap. Allow for corners to be cut out in an L and pleat curve side. Only cut pleats about half way into the sheeting. Do not cut all the way down to the pipe line. See pattern below.
Attach the plastic sheeting to the frame with zip ties starting with the straight edge. Be sure to tuck plastic around the pipe. Slice small holes through plastic close to the frame. Pull ties tight and trim tails. Repeat all the way around the frame.

Screw in threaded adapters to threaded elbow ends

Attach the remaining 5 foot sections of pipe to the adapters to complete the frame.

Cover frame with remaining plastic sheeting and cut to size.

Attach sheeting to frame ends with zip ties from top of frame to half way down. This will allow for access to the inside ofyour cold frame and will allow for airflow on windy days.

Edges of plastic sheeting can be weighed down with metal washers or clamped to frame.

To keep your frame from blowing over in the wind, anchor it down with camp tent spikes.

Slice small holes in top of cold frame plastic to prevent rain water from puddling.

A small cold frame can be assembled in 1-2 hours. Cover your garden or pond to keep plants warm on cold winter days and nights.