stems rotting in Ebb&Flo
I'm not sure that my subject title is entirely correct, as I'm not sure that "rot" is a precise term for what is happening.
However, I'm having quite a few of my herbs, and even a tomato plant or two, rotting off at the bottom. I'm starting my plants in root riot plugs (like the oasis plugs), and transferring them, plugs and all to 4" pots with hydroton to fill the remaining space once roots show and I have true leaves. The plants are thriving. However, I end up with brown streaks down by the plug. Over time, several plants have entirely rotted to the point that the entire plant disconnects from the root system. This has happened to basil, sage, a tomato plant or two, and I can see similar stuff happening to my cilantro. This is happening to large plants, not seedlings (12" basil, 15" tomato plant, etc).
I'm not sure if this is a disease/fungus or moisture issue, as the plugs stay very moist after the ebb&flow cycle (3 15minute cycles a day). I worry that the plant stems are staying too wet and they just eventually rot. OTOH, the roots look fine.
All plants are in one big system, so if this is a disease obviously there is the possibility of everything being contaiminated. However, most plants are doing fine - I've lost maybe 5-6 plants out of 50 or so. A couple more are showing early signs (brown streaks at the base).
I've been treating with a sulphur/water mix by spraying the basis occasionally. However, with no control, I cannot say if this is helping or not.
So, the questions:
* does this sound like disease, or a moisture problem? How would I determine this?
* Is it a bad idea to put the plugs in an ebb&flow system? Would I be better off cloning plants in an aero system, then transplanting into hydrogen as the only medium?
* Is 15 minutes excessive for ebb&flow? I only need 3-5 minutes to fill the table with my pump. Are they drinking/feeding the entire 15 minute cycle?