How to keep algae from forming on greenhouse walls

[Wade's Orchids]

My greenhouse is soon going to go from being a dream to reality and the North wall is going to be insulated and have a thin steel sheet with a rustproof white coating on it. I am planning to hang wire fence from it and use this area for hanging plants. I am worried that algae will grow on the wall and doing something like spraying Physan on it will also mean spraying the orchids. Some of the plants that I will be growing will be very sensitive and besides that, I would rather have live moss than dead moss on the mounts. Any suggestions as to how I should plan to deal with this problem?

[silverstoli]

I have no idea, but I would think fans to keep the wall dry would help and the plants would like the circulation...

[Wade's Orchids]

Fans are going to be in abundance. 1 large ceiling fan, 6 circulating fans, and 2 exhaust fans. Anyone walking in there will need to fix their hair when they leave! I still think I'll have algae if and when any fertilizer water gets on the wall and was wondering how others deal with it.

[chingjervis]

Hmmmm... i think the belated Marilyn Monroe would really love to be in your Airy Greenhouse...lol

[catttan]

Hmmmm... i think the belated Marilyn Monroe would really love to be in your Airy Greenhouse...lol

Not unless the fans were blowing up from the floor.

[Wade's Orchids]

Well, if any of you ladies are in Central Pennsylvania and plan to wear THAT type of dress I will be sure to have the fans properly placed!

[plucker]

Algaecide might help. It is usually chlorine based from what I remember

[raybark]

Wade - you might consider Biosafe Disease Control. (Formerly, they were sold as Zero-Tol and Oxidate. The Zero-Tol was a hose-end spray bottle of concentrate that was diluted as you use it, the Oxidate being a hand-pump sprayer of the already-diluted stuff.)

Chemically, it is hydrogen peroxide that has been stabilized with a bit of peroxyacetic acid, and is applied at a concentration that is a fraction of that in a drug store bottle of hydrogen peroxide. That "cosmetic grade" decomposes in a mater of seconds after application, but because of the stabilizer in the Biosafe products, it stays active until the water has all evaporated.

There is no phytotoxicity shown with the product, so is safe for use on all plants (and I have confirmed that it does not kill moss, even if that's your goal), but it is an excellent algae preventive and general greenhouse disinfectant. The only minor drawback is that the peroxyacetic acid has a slight "vinegar" odor.

[Wade's Orchids]

That sounds great, Ray! Should have known you'd have the answer. Thank you so much.

[raybark]

I actually learned about the stuff at work - When my employer's parent company in France was purchased by another, our businesses were reorganized, and a good friend took over market development in the the agrichemicals division. We had recently purchased DuPont's H2O2 business, and he was anxious to use that in agricultural disinfectants, so asked my thoughts on the matter.

Thought about it for a while, thought "why not?", and then got a few bottles for experimentation (on the company, of course). A bit of research, however, found that Biosafe Systems already had that patented every which way from Sunday. Bad for the company, but a new weapon in my arsenal!