If its the same lamp I vote in.
Yeah its air pruning to some degree. His method involves putting germinated seeds in rockwool and immediately putting them into the media (he uses coco, so do I). I started this party cup seed in rockwool that was in coco from day 1 if that makes sense. No transplant at all. The method I described, if you follow the way the guy says it, lets air pruning to happen without needing to have air pots or fabric pots etc. Its hard for me to explain it but if you watch his video it will make sense.
Edit: if I remeber right isnt most jiffy pellets made of peat? Peat holds alot of water. This method involves daily watering also because rockwool and coco dont hold alot of water. Again details are in his videos if youre interested
Yeah, I know a few of his videos but I have only seen the one where he has used the 4" rockwool cube, removed the outer plastic film and allowed the roots to get air pruned all around the cube. I've not seen the method you've mentioned and it also would not make sense. With the rockwool cube sit directly in coco there will be no air pruning cause it needs air to work. No air, no pruning!
You have done it exact the same way like I did and put it directly in the coco and therefor there is no air between coco and rockwool so air pruning can not happen. Maybe with bone dry coco around the cube..
So its probably 50% genetic, 25% megacrop and of course 25% because of your green thumb..
And yeah, the cheap Jiffy's are made from bad quality peat(PH below 5) and are counterproductive. I've used them one time maybe 25 years ago and only 50% of the seeds have germinated properly. Bad thing, they all have popped up between paper towels before.
Currently I'm using Ugro Rhizo plugs!
Its the same tab like a Jiffy's but made from with mycorrizza innoculated and pre-buffered coco. Coco is naturally rich on trichoderma but there are no mycos. This plugs make sure the seedling/cutting gets immediately innoculated with both types of symbiotic fungi.
BTW, the 3rd one has finally showed her gender so it's time to choose...
Will upload a small unofficial update in a few mins.