Hi All,
I do not know much about wave lengths e.t.c. but I can tell you this. I have
a corrugated plastic green house and all so a glass one. if I grow tomatoes
in a glass green house I will get 4 or 5 trusses before they reach the top
and have to be stopped, at the same height in the plastic one I will only
get 3 trusses, so the plants are searching for light. I would say that a
plastic green house is all right to start plants off, but for long term use
you will have to live with plants that are serching for light, and so less
yeild of crop. by the way melons do well in a plastic green house with no
ventilation as the plastic seems to retain more heat. hope this helps you.

Richard M. Watkin.


Mark wrote in message
m...
Does anyone have a good source for the wavelengths of light
absorbed/blocked by various clear plastics/glasses, and what impact,
if any, this has on growing plants. From the dim recesses of my mind,
I seem to remember that chlorophyll works best with (?) 420 nm or
something like that...

...The reason I'm wondering is because I want to know if I can build a
small greenhouse/cold frame from just any old transparent panels, or
if some will deny the growing plants the right "kind" of light.

Thanks,
Mark