The rate of growth has been amazing, it quickly outgrew a small propagation Air-Pot and the 3 litre size. I noticed the very vigorous fleshy roots tended to thrust out through holes in the base more than is usual with other species, they were determinedly seeking expansion room. When these roots were air-pruned by the Air-Pot container the overall root development benefitted. Foolishly I left the banana on moist earth for a couple of weeks in July, allowing the roots to bridge the air space at the bottom and delve down into the greenhouse border.
Luckily I was able to lift it with roots intact and coil them into a bigger pot. This was a good demonstration of how roots can grow in air if the humidity is high enough.
Other very vigorous rooted plants that I will be interested to try in Air-Pot containers are Agapanthus, Canna and Hosta, these plants seem to crowd resentfully against the side of a normal plant pot forming layers of root instead of being dispersed through the entire volume of compost. When I bought a Blue Storm Agapanthus recently the roots had actually split the pot open!
Finally, a random experiment which I look forward to unearthing is Turmeric grown from a shop bought root. I don’t know if it is particularly vigorous rooted but looks strikingly similar to a banana and is doing well, so here is a picture.