Shade Cloth for Cymbidiums
 

Hi,

I'm looking to take better care of my many Cym's and am getting a greenhouse area built. The builder has bought $350 worth of green shade cloth 70%, but I now understand a white or fawn colour would be a better option for flowering.

It doesn't look like the green cloth can be returned, so is it worth paying again for the white? Does the colour make significant difference, the growers I saw in 90's all used green. I also don't think I can find aluminet in Australia.

I dislike green shade cloth, as much of the transmitted light is reflected green, which is not ideal for plant growth.


This company sells Aluminet

How far from the equator are you? 70% might be too much for Cyms.

I'm around 36 lat, the cym growers in my area seem to use 70% as we have piercing sun in summers with little cloud cover, but think 70% may be too much in Winter.

It looks like I'll be getting the lighter colour.

Another advantage of white or beige... it will tend to reflect light - and heat, along with reducing the light by the stated percentage. A thought on making life easier so you don't need a "'summer speed" and a "winter speed" ... maybe instead of 70%, get 60%. Cyms can take a lot of light, that might be a good compromise. Another option, get 2 layers of 50% - the net will be about 75% with both layers, you could just take one off in winter so you'd get 50%.

Here in NJ (latitude approx. 40 deg N), I use no shade cloth during outdoor season (late April till first frost, can range from mid Oct to mid Dec). But, from May through Sept I water heavily (sprinkler for 2-3 hours every other day). To accommodate this treatment, I also use a rapidly draining mix in the pots.

Some of the plants do get a little sunburn, but not badly. And, with high light/lots of water/lots of fertilizer, they grow and bloom very well.

At 36 S, you are about 450 km closer to Equator. I am thinking that you need max 35% shade cloth (the plants can handle high light levels).

Latitude doesn't tell the whole story... If Cym growers where Fredmax lives are using 70%, there's a reason - and Fredmax has mentioned temperatures as high as 35 deg C even now in the spring. That's toasty... I use 45% over my Cym area, to take the edge off, but because of the tempering effect of the ocean my summers are a lot cooler than what Fredmax is experiencing. (I'm at 33.7 deg N) I also have very long duration of summer sun, since there are no trees in the direction of the sun and the yard is oriented east-west. Hours of direct sunlight are also a factor. When I first moved into my house I used no shading for the Cyms. They appeared stressed, got very yellow. They have been doing much better since I took mercy on them.

I left a dozen in the sun (still being in Spring) and they're yellow and brown. This Saturday has a forecast for 40c and there's very little cloud around, so I'd love to get lower than 70% but will likely be out there stressing - when I have my hands full with my greenhouses overheating. I need the Cym's to be the easygoing low maintenance orchids so I can keep my deflaskees alive :)

Does the same apply to plastic sheeting for walls? I'm going for white on the same principle, and that the two tone of green plastic and white shadecloth will look strange.

I have to suspect that the basic physics is the same... white reflects and dark colors absorb heat. At any rate, if I'm going outside in the sun in temperatures like you're getting, I'd rather wear white or beige clothing than dark green.