I grow a lot in containers and have become interested in the various air pruning pots available. An active member in the citrus forums has mentioned the RootMaker line. That has a variety of different styles and I'm curious about people's experiences with these different (or other) products. I'm also curious if it makes any sense to place an older tree (5-10 gallon) into an air pruning pot for the first time, or there is a point at which it becomes too late to be of benefit.
In the RootMaker product line, there are the original injection-molded RootMaker pots which look like graduated, concentric pots (i.e., the pot is smallest at the base, has another level partway up the pot that extends wider, and then has another level closer to the top that extends even farther out). There are the RootBuilder II pots, which are uniform in width but have pointed air holes all over the sides. Finally, there are the RootTrapper canvas containers, which purportedly also air prune, albeit in a different way than the plastic pots which have designated air pruning locations.
Most other air pruning products I've seen resemble one of the above designs. The RootMaker website showcases these different designs but does not explain the advantages/disadvantages, or why one would choose one design over another.
So, in summary, I'm curious about what designs you've used, if you know which use cases work better for the different designs, and if there's a point in the tree's development at which it's 'too late' (i.e.,. no benefit gained) to start using an air pruning container.
Thanks in advance!