How to Build High Tunnels and Cold Frames
If you're planning on gardening beyond the normal growing season, consider using either a cold frame or a hot bed. Cold frames are like mini-greenhouses that use the sun's rays to heat a garden bed. High tunnels are also like greenhouses, but instead are built on a frame, similar to a Quonset hut. Cold frames are usually square or rectangular and use windows to capture the sun's rays. High tunnels are built on arched supports and use clear plastic for solar energy gain. Does this Spark an idea?
Things You'll Need
- Wood board 2 x 12 x 72 inches (back)
- Wood board 2 x 8 x 72 inches (front)
- 2 Wood boards 2 x 12 x 24 inches tapering from 12 to 8 inches (sides)
- Soil
- 24 x 72 window (top)
- Shovel
- Screwdriver
- Drill
- Screws
- Measuring tape
- 8 pieces of 10-foot-long, 3/4-inch light PVC pipe (ribs)
- 8 to 30 pieces of rebar
- 4 pieces of 30 inch 3/4-inch light PVC pipe (ridge)
- 3 pieces of 4-way 3/4-inch PVC connector
- 2 pieces 3-way 3/4-inch PVC connector
- 20 x 20 foot sheet of clear plastic
- 20 tent stakes
- Rubber mallet
- Utility knife for cutting plastic
Instructions
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Cold Frames
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1
Line up the boards so that the 12-inch sides face toward the back of the frame and the 8-inch sides face the front.
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2
Screw the sides to the back and the front, creating a box. The box will taper from 12 inches in the back down to 8 inches in the front.
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3
Choose a place for your cold frame.
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4
Turn over soil inside the frame or add extra soil.
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5
Lay the top over the frame.
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6
Plant seeds, vegetables or flowers.
High Tunnels
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7
Choose a location for your high tunnel. You need a minimum of 10 by 10 feet of space.
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8
Measure where your rebar posts will go along the sides. They will sit every 30 inches on each side of the high tunnel.
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9
Sink your rebar posts. Use a mallet to pound the rebar into the ground about 15 inches deep, leaving a 15-inch post every 30 inches.
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10
Connect your first ridge pipe to the 3-way connector and then connect the other side of the ridge pipe to a 4-way connector.
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11
Connect the second ridge pipe to the 4-way connector and add a 4-way connector to the end of the second ridge pipe. This should form a chain or line straight across.
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12
Connect the third ridge pipe to that 4-way connector and add a 4-way connector to the end of the third ridge pipe.
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13
Connect the fourth ridge pipe to that 4-way connector and add a 3-way connector to the end of the fourth ridge pipe.
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14
Connect the ribs to the open connectors on the ridge. A rib should be on either side of the ridge to make a rib-like cage.
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15
Insert the bottom portion of the rib pipe into each rebar post.
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16
Use a rubber mallet to tightened all joints.
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17
Slide plastic over the frame and use tent stakes to secure into ground. Cut plastic to fit with a utility knife.
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18
Use is the same manner as a greenhouse and plant seeds, vegetables or flowers.
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1
Tips & Warnings
Ask a friend to help construct the high tunnel.
References
- Photo Credit Traditional cold frame image by Shirley Hirst from Fotolia.com
