protected cold frame
Brian Whyer (Wed, 21 Jan 2009 01:47:25 PST)

Thanks Uli. I encountered these tyemperature-controlled devices as a
youngster about 70 years ago, but did not know that they were hydraulic.
Are they still being made? Energy-saving, I'd think and need to be brought
back or re-popularized for today's world

These are available in almost any Garden Centre, or from a greenhouse
supplier, in the UK. Just Google "automatic window opener". Different
lifting strengths available. Some get tired after about 20-30 years or so,
and stop working. I guess they leak slowly.

Brian Whyer, Buckinghamshire, England, zone ~8