Will water prune roots with an air layering pot?

Question

I've been looking at the root pruning pots and wanted to experiment with them this year. I've seen people on YouTube using A cloth like root pruning bag and they'll set it in a kiddy pool of water. They just keep the water topped up and the pots wick up what they need.

My question was, when the roots grow down to where the water level is, will the root tips die and cause back branching on the root the same way it does when exposed to air?

I can see it going either way. I could see the plant knowing it and grow into water and killing the tip that's touching it, causing the roots to back branch. I can also see it rotting and allowing bacteria in. Obviously, plants can be grown this way, because plenty of plants (non-water plants) grow beside water and there are the YouTube videos where they get better than expected results, but does it prune the roots and would it be healthy for the plant in the long run, like if you were trying to start trees from seeds or cuttings and were worried about them drying out.

Answer 1

This is my kiddie pool sub irrigation planter with a couple of dismal looking tomato plants, and one bag with 4 corn and one Apple tree seedling. I probably over did it! Two of the corn look very weak.

What I've observed, apart from the mosquitoes breeding in the water, is that the roots grow into the water which is well oxygenated. So, they don't prune unless you let the pool dry out, and then they die back.

Because it's sitting in water mostly I would expect the roots to circle at the bottom. So, I wouldn't use this method to prepare trees for transplanting.

A standard root pruning pot, such as the air pot, has a gap at the bottom to prune the bottom roots. And they pretty much stress that you need to drip irrigate them since they dry out so quickly.

So, in summary, using air permeable bags made from recycled PET bottles ( preferably from ones known to have low lead levels ) is good for growing plants for final use, but I doubt that they'll be as good for transplanting as a proper air pruning pot.

Edit: this is the corn cob from the above plant after microwaving. Surprisingly all the kernels are fertilised even though it's the tallest plant of 4 from one grow bag. It appears foreshortened due to the angle the picture was taken.