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Old 08-10-2005, 06:57 PM
Don
 
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Ted Byers wrote:
"Ray" wrote in message
...

Doesn't that raise the question about what the red pigmentation does
(assuming all other mulch properties are identical)? Is it the reflected
red light back to the plant that makes a difference or is it a change in
the ground temperature under it?


Yes. ;-)

Both are likely to be happening. Any red light reflected onto a leaf will
likely contribute to photosynthesis, and possibly other processes. It is
certain that any light absorbed by the ground will be converted into heat,
producing nonlinear changes in soil temperature with depth. Now
understanding that process is considerably more complicated, involving
conduction and transport of heat, but the salient point is that light
hitting the soil will raise the temperature of the top layers of the soil,
and that will have the usual effect on reaction rates in the plant's roots.

How significant each process is is a different matter that can really only
be determined experimentally. I know the agriculturalists I know talkof the
importance of soil temperature, but I personally have not heard them discuss
the colour of the ground.

Cheers,

Ted


The following is copied and pasted here from the Lee Valley site -
www.leevalley.com . Do orchids have this phytochrome, the colour
sensitive protein the stimulates rapid growth?
Don

Super Red Mulch
Super Red Mulch - Gardening
From time to time research comes up with some astounding results. This
is one of them.

When this red plastic mulch is put on the soil under tomatoes, it will
increase yields by up to 20% over black mulch, and makes the fruit set
earlier. It works by reflecting a certain spectrum of light back to the
plants, which in turn triggers the release of phytochrome, a
color-sensitive protein that stimulates rapid growth and development.

The research was done by a number of universities and our own tests
proved it accurate.