Re: What is a greenhouse? and information on a greenhouse

Well Jamie, I don't want to do your homework for you, so I'll just tell you 
the basics about greenhouses and give you some links for more detailed 
information.  A greenhouse is a special building that is used for growing 
plants in an area where they wouldn't normally grow that well.  Greenhouses 
may be almost as big as a football field, or small enough to fit in your 
backyard.  They are buildings that have walls and a ceiling that are all 
see through (these are usually made of glass or layers of a special plastic 
called "polyethylene" or PE) and rows of plants growing inside.  The clear 
walls and ceiling of the greenhouse allow the sunlight to pass through 
(which plants need to make their food in a process called "photosynthesis") 
while keeping the cold air, birds, and bugs out.  By watering and 
fertilizing the plants regularly, keeping a good airflow through the 
building, and heating it in the winter, greenhouse managers can grow almost 
any kind of plant year round.  A greenhouse could even let somebody grow 
tropical flowers in an Alaskan winter!  One problem with greenhouses is 
that they can be expensive to operate on a large scale.  Another problem is 
that, since plants need carbon dioxide to survive, they must also run 
propane powered CO2 generators inside them so that the plants will stay 
healthy.

For more information, check out the Texas Greenhouse Management Handbook at http://aggie-horticulture.tamu.edu/greenhouse/guides/green/green.html

For information on the kinds of  plants that grow well in greenhouses, 
check out the Michigan State University website at  http://www.msue.msu.edu/msue/imp/mod03/03900061.html