Air-Pot Garden Extras
Air-Pot containers have unusual cuspated walls, sort of an egg box configuration, made up of closed inward pointing cones and open ended outward pointing cones. There are no flat surfaces on the inside of the container to deflect roots and start the spiralling process.
The inward pointing cones direct the roots further outward to the open ended cones where, because the air density in the soil is too great, the roots dehydrate and are effectively pruned.
The plant responds to this "air-pruning" by sending out more roots to compensate for the loss which leads to a dense root system with a vast number of active white tipped roots.
The porosity of the Air-Pot wall also creates better conditions for bacterial activity and thus increases the amount of nutrients available to the plant. With so much root right back to the stem, the root system is very efficient in its use of all the available water and nutrient.
Plant vigour and health is therefore guaranteed.
Now for the real thing!
The two photos below are of an Oak called Quercus accutissima. Like most Oak species they have a very agressive tap root, which is the first root to emerge from the acorn and when grown in containers do not generally have a lot of small fibrous roots
In Air-Pot containers the taproot has been gently air pruned and controlled, not deformed and the fibre is plentiful, for an Oak!