In article , Jane Ransom
writes
In article , shazzbat shazzbat@spaml
essness.fsnet.co.uk writes
I believe the main disadvantage is that plastic does
not admit light to the same degree as glass. This will be of most relevance
in spring when light is at a premium, or if you are at northern latitudes
this will be a consideration. Also plastic will get scratched etc and
gradually become opaque, cutting light down even more.

Doesn't it also become very brittle with time? Especially if it is in
the sunlight, which, obviously, a greenhouse is!!!!!!!!

I thought perspex was less suseptible to this than some other plastics.
And aren't the greenhouse perspexes a different formulation which
improves light transmission and reduces damage from light?
--
Kay Easton

Edward's earthworm page:
http://www.scarboro.demon.co.uk/edward/index.htm