I just posted on your other thread.

Air Pots, especially those manufactured by RootMaker Corp. work very well. Their air pruning containers are based on the 4 inch rule, and air root pruning. When used correctly they do an absolutely fantastic job developing a tree with a strong root system, thus producing a strong and very healthy tree with excellent growth. - Silica

What Silica said

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Airports are an ideal nursery for fungus gnats.

eSilviu, sorry to hear you have had problems with fungus gnats. I have grown many, many, many trees and various plants in Air Pots manufactured by RootMaker for more than 15 years. So far I have never had a fungus gnat problem, - not once - ever. RootMaker air root pruning containers are the only containers I ever purchase. - Silica

Well, I had 3 pots used last winter and all of them were populated by gnats... not millionsure of gnats, but enough to be a nuisance.

If the pots are big (like 4 gallon or more), then it may be ok to use air pots. For the smaller ones, you can't let the soil to dry 1-2 inch around the circumference in order to kill gnat larvae, because the whole soil will become too dry.

I still use my air pots just because I paid for them, and are better than regular pots. In the meantime, I made myself some fabric pots that seems to work (for roots) as well as air pots and don't let the gnats reach the soil.

Steve, do you get any circling of roots with your pots?

very little if any. My roots all seem to be very well branched.

I did similar experiment with 5 liters water bottle, transformed in 3 litters pot. There were no root circling and roots were very well ramified inside the soil.

Some images of my pots:

Roots exiting through the mesh from the bottom of the pots:

eSilivu, how did you make your own fabric pots? I also kind of like the white on your trees...Cool looking..Nice job!