by Gail and Ron Wilcynski

Cold Frame Greenhouse

My husband, Ron, and I live on the east side of Placerville at approximately 2,400 feet elevation. 

We wanted a greenhouse to protect the plants in our raised-bed garden from frost and to lengthen our growing season.  We also wanted something affordable, durable during winter snows and wind, easy to build, and easy to remove during the summer.

Placerville was at the end of a long road for many pioneers traveling across the U.S. in covered wagons; so it is only fitting that we built what we call a “Prairie Schooner Greenhouse.” 

The prairie schooner greenhouse works great! Here are the materials we used:

  • We used gray electrical PVC pipe for the hoops because they are durable but bendable. 
  • We used white PVC pipe for the base because they are a good size and easy to hook to the electrical pipes with PVC fittings and plastic pipe cement glue.   PVC frame
  • We used metal clamps as hinges to secure one side of the greenhouse lid to the raise-bed garden box
  • And we used Sunturf polycarbonate greenhouse panels and the corresponding foam strips.
  • We made air vents in the tops, using Velcro to hold the vents shut.
  • And used a simple string-tension system to open and close the greenhouse lids. 
  • We pre-drilled holes into the panels and PVC pipes so they would not split when we screwed the two products together.

Velcro to shut vents

We found that plants grow well when we open the greenhouse lids during the warmer part of winter days.  The plants are forced to endure a breeze which helps them grow strong and full instead of thin and stringy.

Total cost of building two 4 x 6 foot prairie schooner greenhouse lids was approximately $300. 

Without additional passive or active thermal storage this cold frame design is not capable of keeping summer plants truly warm all winter. But it can extend the growing seasons and keep the frost off your tender plants. 




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