In article danangela-
,
says...

We've used red plastic the past two years and will use it again this
year. Two years ago we grew tom's in containers and last year in a
large planter box/raised bed. I don't know if it made a difference, but
we had great yields and very healthy plants here in Seattle. We have
long summer days but not as much heat as other areas. The plastic
helped with moisture loss so we didn't have to water as much, which gave
us good, firm fruits. I think it also helped with heat reflection &
retention. As far as the claims of the red reflecting the best light
spectrum, I'm no agricultural scientist, but I was very happy with the
plants' vigorous growth and high yields.


I cannot say for sure, but the better heat reflection
sounds at least possible. Regular heat (that we can
feel but can't see) is in the infrared part of the
spectrum, just below visible red. A red-looking object
reflects mostly the red part of the spectrum, so
perhaps the idea is that it will also tend to reflect
lots of infrared (heat.) Dunno if it really does,
though.

If I had really excessive heat, I would be more likely
to consider some sort of shading over the whole plants.


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