algae in pots

[Lucinda Brown]

I was wondering if anyone knew of something you could water orchids safely with that would do away with the algae in the pots without harming them? I have most of mine in clear pots to keep an eye on roots and know more for sure when to water. The algae has gotten bad along the sides of many. Hard to see roots through that. Help!

[Cynthia, Prescott, AZ]

Physan 20 will probably slow down the algae growth, but I would have to warn that you would want to be very careful how much you use. I ran it a little higher than the recommended and ruined a lot of flowers, especially the white ones. I now am starting to use it at a reduced rate once or twice a month in my fertilizer water.

I think a much bettrer plan would be to get solid color pots of the same size and slip your clear pots inside. remove your original pots when you want to check on things, but you would not be growing any algae in the mean time. Cynthia, Prescott, AZ

[jerrymeola]

Physan 20 works best when used regularly every week or two. Do not try to clean algae with the product, it does not work in safe levels.

You can also use hydrogen peroxide for the same result. Again do not overdo it. Small spraying weekly are best.

I know a nursery that claims he only changes bark every five years or so because his regular use of Physan 20 slows the decay of bark. There is some logic to this claim but I only pass along the remark and can not confirm it as I do not use the product regularly.