In article , =20
says...
Reka wrote:
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Okay, I know a little about orchids, but more about orchards, a subject=
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that I have grown up with. (Shades of those poor newbies who think this=
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is "rec.gardens.orchards"!) Over here, we have problems with hail damag=
e=20
on apple crops from summer to early fall. Thus, hail netting is=20
stretched over the trees during that time period. Very dark green,=20
black, or white nets have been used. It has been proven that the red=20
apples under white netting color up much better than those under the=20
other two dark colors. Now, how this can be correlated to orchids, I=20
don't know, but perhaps it is worth the time I took to write it. And I=
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am a slow typer. :-) I am assuming it could be the extra heat generated=
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under the darker colors that prevent better color. Red apples need=20
temperature swings from cool nights to warmer days without rain in orde=
r=20
to color up well.
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Hi Reka.
We haven't had one of those orchard/orchid confused people in a while now=
..
About the red apples under white netting... You are obviously right=20
about better color with cooler temperatures. That's why they grow a lot=
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of Macintosh apples in Vermont and here in northern New York but not=20
much farther south. I bet heat isn't the factor with the netting though.=
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I'm not sure a dark netting would cause more heat around the trees.=20
(Also not 100% sure it wouldn't.) I bet it's just more light getting=20
through. You KNOW the apples color up better on the sunny side of the tre=
e.
My first thought was that maybe this does translate into better orchids=
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and the better light that colors up apples would probably help orchid=20
blooming. On second thought, if it's just the quantity of light, then=20
for orchids that need the shade, they need the right amount of shade and=
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it probably doesn't matter if that amount is created by black or white=20
cloth.
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Steve
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I *do* know that the orchardists have to wear sunglasses under the white=20
netting because of the glare. I wonder if the quality of the light is=20
different, though.

From an abstract:
"The effect of hail netting on light penetration and fruit quality was=20
evaluated in commercial apple orchards in Eastern Switzerland. Black=20
nets reduced light levels (PAR) by 18 to 25 %, white netting by 8 to 12=20
% and grey nets (black and white fibres) by 15 to 17 %. No definite=20
influence of black hail nets on maturity and fruit quality has been=20
observed under good conditions (weather, site, small trees with loose=20
canopies, optimal fruit load, etc.) and with varieties for which fruit=20
colour is mainly genetically determined. For ?Jonagold? the light=20
intensity is decisive for development of fruit colour. Reduced colour=20
development under black nets may be observed on this variety. The=20
harvest time can be delayed by 8 to 10 days. Flesh firmness, soluble=20
solids content and acidity were not affected. In general the external=20
and internal fruit quality depends on many other factors which are more=20
important than the effect of hail netting."=20
http://www.actahort.org/members/show...rarnr=3D557_56
So it's a light/shade factor rather than a heat factar, though most=20
farmers here will swear that it is hotter under the darker nets.
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Reka=20

This is LIFE! It's not a rehearsal. Don't miss it!=20
http://www.rolbox.it/hukari/index.html