Hourglass in marijuana stem

A question from a fellow grower:

Three days ago, I noticed one of the WW leaning more than normal. When I tried straightening the plant, it broke off at the soil line. That’s when I noticed that the stem looked like it had been constricted and looked like an hourglass in the middle. Now I’m down to two plants. Tonight, I was watering and inspecting and again noticed that my NL was leaning. Closer inspection again revealed the hourglass figure on this plant, and also on my remaining WW. I’m following the same feeding schedule I’ve been using successfully for over a decade. There is no strange colorations or disfigurement on the leaves. I always use fresh soil for every grow. At the end of the grow season, I take the planter out and scrub it down with soap and water, followed by a liberal dousing of bleach. A quick rinse and we’re ready for the next grow.
What can be causing this problem with the stems being constricted like this?

It sounds like you’ve done everything you are supposed to do to avoid diseases in you soil, but nonetheless it still sounds a lot like damping off. Here is an article on damping off. Without a really clear picture and further info it will be hard give a better diagnosis. Here is the link about damping off by Robert. If you have anymore questions or new information about your plants, please do come back and let us know.

I read the article on damping off a few days ago cause it sounded like what I was experiencing. One difference though, the pictures in the articles were of very young plants. Mine are 5 weeks old and very bushy, plus there are no other signs of distress in the plants. No spots, streaks, curling of the leaves, etc.

Younger plants are more susceptible, doesn’t mean it can’t happen to older plants, 5 weeks is still not that old. Sorry, again, I don’t have enough information to give a better diagnosis.
Maybe if you have a clear picture you can post? 5 weeks with lots of bushy growth, you should be able to save a top by cloning it.