The Air-Pot wall material is normally sold cut to precise dimensions to suit specific diameter plastic bases, and is simply wrapped around these bases to build the pots which range in size from about 10cm diameter to the largest at around 40cm. This range of sizes suit nearly all the usual pot plant requirements from seedlings to quite large shrubs and saplings, but sometimes a truly huge container is needed and the Air-Pot wall material can be used to to make these mega pots too; they will just lack the ready-made plastic base. I made a wooden platform out of a cut-down pallet to provide a base for a 50cm diameter Air-Pot, this large pot was needed for a Yuzu citrus tree which has put on a lot of growth. The air-pot.com garden website now includes an option to select a large diameter and height under the heading “Build your own container”, the wall material will then be cut to suit.
I reckon my 50cm diameter pot-on-a-pallet will still just about be moveable by two people possibly by sliding poles or bearers through the pallet like a forklift but it will be a sweat, any larger than this and I think the pot will be a permanent fixture. Perhaps that azalea on the patio growing in a disintegrating half barrel would benefit from a larger container, the old barrel could be stripped away and a length of Air-Pot wall wrapped around with space for some fresh compost?
Another way to use the wall material is to set the large bottomless container directly onto earth, roots may go down into the soil below but if it is never going to be moved this does not matter. By creating this large container it is possible to build up a huge depth of really good quality compost and manure, effectively you have a instant raised bed. We used 40cm high wall material wrapped around to make a circular bed 1.2m in diameter and filled it with half a bulk bag of compost plus some farmyard manure.
The pumpkin plants which were set into this bed have grown at an amazing rate, far outperforming plants set into the ground with what I thought was a good amount of compost at each planting position. I have heard of pumpkins doing well growing directly on a well rotted compost heap, I guess the Air-Pot raised bed is a sort of super compost heap and we are hoping for a good crop of little Hokkaido Squash / Pumpkin.
As it was quite a big investment buying in the compost I envisage using it for several years, quite intensively topping up between crops to refresh to soil and maintain fertility. Planning ahead I imagine that the great depth of loose friable earth might be perfect for carrots which will be raised up safe from low-flying carrot root fly. The good drainage might also be good for onions.
Was wondering, is there any benefit for transplanting mature plants (ie. my 20yr+ old Night Blooming Cerus) into an air-pot?
I think for a tricky plant like Night Blooming Cereus it might be safer to leave a long established plant well alone, if it seems happy. It can grow as an epiphyte, I believe, lodged on trees in small pockets of compost / leaf debris, so maybe potting-on into a larger container is not essential. These epiphytic cacti do need very good drainage and aerated growing medium which an Air-Pot container can provide so perhaps it would be worth experimenting with some cuttings from your venerable mother plant in a small Air-Pot container. Good luck.