Well, an opportunity arose for me to contribute to/throw gasoline on this thread. Some folks have implied that the condition of rootboundedness doesn't exist, or at least not in hydro, or it can be overcome by modifying your cultivation practices, blah blah. Well.
I have several mother plants which have been alive in flood and drain since last July. I was breaking the branches down on this one, hoping to get it short enough to flower, but this thread and other factors helped change my mind. I'm glad they did. Let's take a look!
When they were 6 weeks old they were placed into 2 gallon pots filled with hydroton and they have remained there ever since. They grew 4 feet tall and stopped. Over time, fewer new shoots appeared, even in response to pruning. Leaves in general became a little droopy and slight signs of deficiencies appeared as well, mostly on lower leaves. Successive cuttings of clones have taken longer to root but there are a number of unrelated seasonal factors that could be at work there.
I think these roots look really crappy. There is barely any new white growth, just old tan, useless rotting mass.
Enopugh of the horror show. This root mass is so dense, that even after soaking the root ball for hours. the mass is very difficult to break up. The water retention is enormous, leading to root suffocation and death. I flood twice a day and it is too much for this plant.
TO be fair, no one should keep a plant alive in hydro that long. Hydro is good for cropping not long-term maintenance. I'm sure someone can argue that statement with me, but it is a little like the pot-bound argument; anyone will argue anything on RIU.
Conclusion: In the specific hydroponic practise I follow, rootboundedness does indeed exert a negative effect on plant health in the long term. Generalizers may generalize; I am presenting my facts. My current plan of action is to kill the rest of my mothers; paging Dr. Freud!
