Gardening and Horticulture - Building a Green House

Left suggested me to post this question in Gardening forum instead of Building Sunroom forum...

I want to convert our back patio that has a concrete slab and a plastic sheet lined roof into a greenhouse that will be warm enough to grow herbs in the winter. I am thinking about a knee-height surrounding and probably enclose the whole greenhouse with plexiglas.

Is brick good enough for insulation? Should I use other material to make the lower surrounding?
Is Plexiglas a good material for making a greenhouse?
How thick of a Plexiglas do I need to keep temperature constant?
How do I connect the glass walls together and to the roof?
What kind of roofing material do you suggest?
Do you know any place where I can find step-by-step instructions on building a greenhouse?

Thanks!

Go to your local building center and look for their book section. Also, you can check your local library. Ortho Books puts out a book titled "How To Build & Use Greenhouses" which is excellent. Contains plans, how to, directions for construction, materials to use, etc.

Also, you can contact your local Cooperative Extension Service (find in government pages of your phone book) which is listed under your state's land grant college initials. They will have plans available for a lean-to style greenhouse suitable for your geographic area.

Your success depends on lowest winter temps unless you wish to add heat and also amount of sunlight available unless you wish to add florescent lights. You can also raise herbs indoors using florescent lights. The 4' workshop light is sufficient using the regular light tubes. No need for expensive light tubes.

Best of luck, Retired commercial greenhouse/nursery owner