Airpots good or bad ? The first FOUR inches ???

I have been growing In my 5x5 closet now for about five years. I , like many other I assume went to the Internet to learn the tricks of the trade. Early on I stumbled upon a somewhat “ star” in the growing community and decided I liked his videos and his thinking. He , at one point was growing with airpots ( the plastic ones with the points all over them NOT the fabric pot ) . He explained that the first four inches were the most important. He basically stated that starting a plant in an airpot would “ train “ the roots; it would “air prune “. I instantly ordered small airpots on amazon. I also ordered the next size up ( five gallon ? ) so that I could transport and have a grow from start to finish in these pots.

For the next four years( my first grow with garbage seeds went well ) I experienced my plants beginning to die in week five of flower. I always let them run out and what I got was what I got. I grew in soil , coco , promix , etc and had the same results. I posted questions , called the “ grower hotline “ and was told it was everything from overwatering to under watering to salt build up to high PPMs to water temps too high to when watering and a few more things I can’t remember.

I have a great light , great climate control , check my PH. In general , I had everything pretty much perfect yet my plants were dying in week five. As irresponsible as it sounds; it’s all I knew. I was happy with the end result so I really never really dug deeper .

So I came to the conclusion these airpots are NOT good to start your seedlings in. I believe that it promotes an unhealthy root ball . This goes totally against the “ first four inches “ theory. At harvest, my root balls were the size of a softball. ( I know , why didn’t I see that years ago ? Hush )

Recently I popped my beans and transplanted to a simple Solo cup. The difference was / is amazing ! My plants are flourishing AND I have them in the larger airports . ActuallyI have two in the airports and two in the smartpots ( fabric ). Either way , my error was trying to start them in the small airpots.Anyone have any idea what the science may be behind the airpot not performing? My opinion is that it’s a good theory but when dealing with the small pots; when watering , the water travels down too quickly and roots are trained to go downward. I’m a fan of the transplant to an airpot but staring them in one is a no go for me.

Air pots, air trim, not allowing the root ball to grow..

While it's hard to know everything about your environment to give an exact answer, I have "helped" many people learn to grow.
What you describe (softball sized rootball) is something I have seen repeatedly.
Upon closer examination, it was almost always a result of too infrequent watering, or allowing the rootball to dry out too much.
The reasons were different however.
Some had too big a pot, and though watered somewhat frequently, the edges never got moist.
Some had too small pots and watered late regularly.
But it was always root damage, and roots retreating to moist zones.

I have noticed over the years, that I usually have to make a point when instructing people, that frequent smaller waterings are better than infrequent large waterings.
You are looking for that sweet spot of moist not wet, and a fabric pot, or an airpot, will dry out quickly from the outside in.
My soltion is simply watering smaller amounts more frequently, at the edges of the pot.