I wanted to do a dissection of my Autopot pots with an insert that I 3d printed because I wanted it to be more “Autowatering planter” like.
I made it so there was approx a 1" airspace between the coco and the nutrients. This is SOP in an “autowatering” style planter. I then had 4 corners where the nutrients would wick upward. You can see just how saturated it got, so coco is very good at wicking. I did NOT top feed.
The interesting thing is look at the roots. They do NOT go to the divider I made. I was very much expecting the roots to grow through the slits as well as into the four corner wicking wells.
Now just to be clear, this is ALOT more air and space than they would using any other bottom substrate like clay balls.
Why do you think the roots stopped? They were NEVER in stagnant water. I’ve done previous grows with coco all the way to the bottom. Roots went right down and in the reservoir itself. But not this time.
These things went through a serious amount of water, so uptake and processing were never an issue
I didn’t have any root rot, but I’m not sure my spacers did a whole lot.
Hmmm? This is very interesting 
Looks like they air pruned, similar to what fabric pots do.
Interesting theory, although when mounting a DWC you have to leave an air space between the net pot and the water, roots do go down 
.
Maybe that happens because net pot is dry an they “smell” the water below.
In this case, as water goes up they have no need to go down, using a fabric pot instead would force them to go down as they could not wrap around as with the plastic one … 
I did just grab some 2 gallon fabric pots, so I’m gonna see how to integrate them.
Here’s what I’m thinking. Bucket, 3d insert, layer of coco for wicking, fabric pot… ???
Saw recently an oger putting river stones under the fabric pot to avoid air problems for roots, maybe it could work if you fill that space …
I’ve seen a fabric bag inserted into both a bigger fabric and plastic pot. Just remember seeing a photo.
That doesn’t make sense because the goals of fabric pots are root oxygenation and root pruning, that doesn’t occur if blocked by plastic pot …