OK, I know this is an old post, but I need to give you some information. Physan should never be mixed with ANYTHING! I found this out the hard way. I use Physan as a drench solution in my plants a few times a year and since I started doing it, I have never hard black root rot problems. So far, so good. Well, one morningI decided I would be "smart" and save time by mixing Physan, MSU and liquid kelp fertilizer together. BIG MISTAKE! The Physan turned the liquid kelp into a gelatin gooey mess that literally destroyed my watering can and stained my hands for days. It was stringy and stunk. It took weeks to get out of the plants. Fortunately the plants seeems none the worse for the wear. I have now learned not to mix anything together EVER! Hope this helps.
As a side note, I am starting a twice a year regimine with Phyton 27 as a preventative the same way Norman Fang does in his greeenhoused (
Hobby Growing). Once in the spring when things go out and once just before they come back in. last year I lost 25 plant to various fugal and bacterial problems and I will not put up with that again.