White plastic shadehouse

[craigallen]

I have a small greenhouse with a white plastic slip over cover. Can orchids grow suitably under white? I have several other small greenhouses, with a clear plastic, and green shadecloth cover, and they seem to be doing okay in those. But does white cut down the light, or alter the UV spectrum too much?

[I. C. Unicorns]

Chlorophyll does not require ultraviolet light to work. Clear glass filters out most of it also. So, don't worry about that.

[craigallen]

Thanks for the answer... my only remaining concern now is that it cuts out too much light. I guess I'll know for sure at flowering time!

Craig.

[jerrymeola]

Measure the light to be sure - why guess - you actually do not need a SLR camera - any auto-exposure camera will work just be careful that you are only reading the white paper

Measuring light levels with an SLR camera

[craigallen]

Just as a postscipt - since adding these posts a few years ago, I invested in a white plastic 'greenhouse' to house my growing collection. The orchids in it have now been through 9 mths of growth, and are starting to flower. The results have been amazing - and I now have no concern about the colour... the flowering rate is way superior to the shadecloth house i'd tried before (due largely to some limited insulation at night and 'greenhouse' effect during even the coldest winters' day).

[patticake]

Fantastic!! BTW- BACK!! We would love to see pictures, if you have any. Congratulations on the growing success.

[jerrymeola]

I think the reason for your success is that the white does not block as much light and you are growing under higher light levels.

I also find that in constructing a green house and its larger collection, you become more regular in watering and fertilizer. All good things.

I mostly wanted to add some research going on in Florida with growing under red or blue covers. Apparently, Orchids do not see any other colors. Using red or blue allows you to increase the light level reaching the orchids without burning. It will be a year or two before results are known, but it is interesting. My next shadehouse is planned to be red.

[jay]

Jerry, this is the same concept for using only red and blue LED bulbs. I have several LED panels that are 75% Red 25% Blue, and the orchids seem to love them. I look forward to hearing more about this in greenhouses.

[craigallen]

Thanks for the interest - here are a few links to photos.

Aussie Victory on Flickr - Photo Sharing!

and

Den. Flinders_011 on Flickr - Photo Sharing!

There are about 25 more plants yet to flower this season - mostly Aussie natives / hybrids, based on Den. kingianum and speciosum. SO, in short, cold-growing orchids that don't need any supplementary heat in winter to get them through a pretty chilly Canberra winter. We regularly get below 0 degrees C (32 F), although the coldest I've recorded in the unheated greenhouse is right on freezing. But no sign of any cold damage this season.