Beneficial bacteria & algae/danger of Physan
 

I was wondering if there was any danger to preventative treatments with Physan. I have some lovely Onc.'s and intergenics potted in medium to small bark mix, but I cannot see the roots as the pots are opaque. Unlike my Phal's, I can't pop them out to peek now and then.

I keep the oncidium / intergenics moister than the phals and I fear mold/rot. I have some Physan, but I don't know if sterilizing the roots and medium is really good for them. Any thoughts?

I've done it with no problems. But I'm not sure if it is meant for that use. I've even soaked mounted plants in it. But if you need to use physan on the medium, it might be time to repot.

When I worry about bad stuff going on in the pot, I usually either repot or let it get really dry for a few watering cycles.

I treat my orchids with physan during the hot summer months here in Florida. I drench the growing medium completely. It's never caused any problem. Norman's Orchids (orchids.com) says they treat all their orchids monthly with physan.

Yep, I do it about bi-monthly. Just mix up a couple gallons, and soak everything. It doesn't really kill the algae, which I find odd.

A friend a while ago told me he used in his stock solution And i do it know and found no harm done to the plants.