When you say they are on the patio, do you mean concrete or pavers? Surely the roots wouldn't go far out of the bag in that situation ... in which case I'd let the "late air prune" with some straggle.

Wow, looks like this thread continued without me noticing! It's great to see the interest. Legacy, I think that's a heck of an idea! I'll get to work on it soon. I tried playing around with a few different "molds" tonight, seeing if I could use something such as a tuperware container to form the screen. It partially worked, yet I couldn't get the screen to maintain shape after pulling it out from the tuperware. I used two containers of a few different sizes that were stackable. One container served as the bottom half of the mold and the top container as the top half and also as a compressor. I had mixed results. Ultimately I was attempting to compress a shape without having to make vertical cuts in the sides as you had suggested. I was hoping it would maintain shape while I pulled it out of the mold so I could staple the sides without having to make cuts. But alas, I could never get them to hold shape no matter how much force I applied compressing the two containers together. So I'm going to try the vertical cut technique you had suggested. I'm really exited about it as it should make the process very efficient if I can get the process perfected. Tim, that's a great idea too with the tomato planter. I've got a similar situation in my back yard: lots of concrete, but little soil. If I'm ever struck by the tomato bug, I'll definitely give it a shot. If you decide to try it next year, please let us know how it turns out! James thanks for sharing your experiences too. I'm glad you're having success with the air pots. That drives me even further to try and perfect this DIY attempt. I like your idea of using plastic buckets with holes burned in them, however I am at a loss for spare buckets at this time. But in the long run such a container would definitely be more structurally sound and last nearly forever. If anyone has more ideas, please share them with everyone. Thanks again! -Brandon

The only thing that I don't like is that the filter in the air cleaner is in the attic and not very accessible, so I don't do it myself. I would much rather be able to climb on a step ladder and unhook the ceiling grille to change the filter. Would it hurt if we put a filter there as well (like by restricting too much of the airflow) or help in any way? Would adding a filter there slow down the rate of how often we have to change the air cleaner one? (I think right now it is a once a year recommendation.)

They appear to be just bags of charcoal, like aquarium charcoal, which you could buy for much less money and just put out in an open dish or your own fabric bag. IME charcoal works great but primarily for closed areas like closets, not so well for a whole room, although it helps some.