re: Have you ever taken a science class?
"History of the greenhouse
The Romans, in their wisdom, were the first people to use a structure to give plants protection.
They used heated pits covered with translucent slabs of rock to form primitive greenhouses.
It was, however in the days of the great explorers that the glasshouse (to give it its correct name) came into its own in the 17th and 18th centuries.
Strange exotic plants and seeds were being bought back to this country, from far distant lands. "
http://www.greenhouses-uk.com/greenhouse_story/greenhouses_history.htm
More complete history:
http://ag.sfasu.edu/horticulture/hrt321/ghhistory1.html