Infrared Heating, Soil Heating
The double layer acrylic material that is called S.D.P. in Canada and Acrylite in the United States has become more common over the past five or six years. It was first installed on several cold frames at the Vineland Research Station about 10 years ago but there was not a lot of interest since it had to be imported from Germany making it very expensive. S.D.P. actually is a short form for "Stegdoppelplatte"" and is now made by Chemacryl Plastics in Niagara Falls, Ontario plus GyRO Industries in New Jersey.
Source: • Colorado State Flower Growers Association Bulletin #372
Keywords: Sdp Infrared