I think you may have misunderstood the shade cloth recommendation. It was
not to use it instead of the rigid roof, but in addition to it.

The idea is that you're looking for a structure to enclose and protect your
plants from the elements. A solid roof - I'd still go for the clear, even
down there - provides the mechanical barrier. The shade cloth is your solar
intensity control, and as was also recommended, you can use different
"weights" of shade cloth to create zones of different light intensities.

The reason I would still go with the clear roof is mathematical: assuming
you agreed with the shade cloth supplement, you have to consider the
availability of the transmission levels and the result through the roofing
AND cloth, as the shade factors multiply. That is a 50% shade cloth results
in roughly 47% or 39% transmission under the clear and white roofs,
respectively.

Using your own argument, if you need something to get full sun, you can move
them outside, but then you don't have protection from the frequent rain!

I guess that for me, it's more of a case of the white cover limiting your
degrees of freedom. I can always add shade, but I cannot add transmittance
through the roof!

--

Ray Barkalow First Rays Orchids
http://www.firstrays.com
Secure Online Ordering & Lots of Free Info!


"bb" wrote in message
...
On Fri, 16 May 2003 06:13:04 -0400, "Ray @ First Rays Orchids"
wrote:

Thanks Ray, and the other posters, for the input on my roofing
decision.

Different manufacturers may very well have different transmission levels
in
their polycarbonate (note the "a") sheets.

That turns out to be the case. One manufactures gray panels let in
20% sun, the other, 84%. Same with the white, one lets in 45%, the
other 78%. I decided on the 78% white panels based on my local orchid
supply houses recommendation, and the information on the orchid
society web site about how much sun to give different varieties. From
what I could tell, 80% sun was about the most recommended. If I found
some need 100% sun I can move those outside. Being on the west
central coast of Florida, 78% sun is still one heck of a lot of sun.

My main reason for going with roof panels rather than just shade cloth
over my trellis was to control how much water they are getting when
we're in our rain every day season. With a 78% sun panel I'm
expecting to have to build another zone or two with shade cloth
anyway.

Once again, thanks to all for the help. Any Ray, I enjoyed your web
site. One of these days I'm going to try the hydro thing so you'll be
hearing from me.

bb