Greenhouse shading

[dennisl142]

I have been growing orchids under lights for 3 years and am now going to make the big move and buy a green house. I grow compact Catts,Oncidums and Phals. My greenhouse will have an east west orientation. How best will it be to use 80% and 90% shade cloth for the plants. Should i place the 80% cloth at front for the Catts and Oncidium and the 90% at the qback for the Phals. Your comments will be greatly appreciated.

[Ray]

I'm reading this through Tapatalk, so can't see your details, but I've never heard of anyone using that much shade!

Where are you located, at what is the area around the greenhouse like - trees, hills, etc.?

I am in southeast PA, and the folks at Parkside Orchids use 30% shade year round, adding a second layer in summer. I am 15 miles from them, but have tall trees in the area, and am on a hillside, and I found that even 30% was too much.


Ray Barkalow
firstrays.com

[Orchidgirl83]

I do not grow in a greenhouse, but have looked into what it entails, so I may be wrong. I think that the percentages are how much light it blocks, not how much it lets through, so 80-90% would be way too heavy.

[Subrosa]

And remember that if you put two layers, each of which blocks 30% of the light, you are NOT blocking 60% of the light. The first layer blocks 30%, and the second blocks 30% of the remaining 70%. Two layers let about 49% of the light though.

[dennisl142]

I live in columbus,ga. The sun in the back yard comes over the tall oak trees and moves over the house. I want to orient the house east west as the sun will move over the house from the east to west. Thanks Ray for the great advice about shade cloth. I got that figure from someone who is jn the business of selling and raising orchids.

---------- Post added at 09:44 PM ---------- Previous post was at 09:34 PM ----------

What i am confused about is if i am going to grow Catts.Onc and Phals do i hace to put up 50% cloth in the western part of the house to accomodate the Phals.

[Fairorchids]

Phals require 60-70% shade.
Catts & most Oncids require about 40% shade.

If you build a GH with double wall plastic sides/roof, that absorbs about 10% of the light.

Best orientation is N/S if you want multiple shade zones. If you are stuck with E/W, you may have to do 30-35% on the outside, and then another 40% inside over the Phal bench.

[JDT]

I am in South Florida and most people that I know and even some of the major nurseries use only 60% or 70% for all of their orchid houses. I currently use 60% and will be replacing my shade screen after the first of the year and can not decide if I want to stay with the 60% or go to the 70%, leaning toward staying with the 60%. Using anything higher is over kill and might reduce the sunlight the orchids need to bloom.

[silken]

You could always put the Phals on a lower bench where they are a bit shaded from sun. I use 50 or 60% shade cloth-can't remember for sure. But the Catts get plenty of sun and I place other things in positions that receive less sun by being shaded in the greenhouse by other plants and shelves.

[HighSeas]

I live in Florida and use 60%. Works well for me...everything blooms and many of them several times per year. I do have a few areas where I omitted the cloth altogether. Works perfectly for my Angreacums who seem to really like that burst of late afternoon sun.

[dennisl142]

I live in Columbus, Ga which is basically 200 miles north of the Florida state line. Don't know where in FL you e but I do beiieve that the sun is a little hotter down in most parts of Florida. I think I will start with 40% shade and measure and amount of light that comes through with my light meter. I much appreciate the suggestions.