gently tug on the cutting if there is resistance then its rooted & you can remove the jars. gradually increase the amount of light the plants receives & allow the soil to become more dry (for a brief period)

I let my cuttings get bigger before I pot them on. Actinidia is quite tough, so you can expose it to normal atmospheric conditions for most of the day, providing the cutting doesn't get direct sunlight and where you live has a fairly high humidity.
Also, remember that often cuttings will look like they are rooted because they have put out baby leaves. The plant is actually using energy stored in its tissues to do this. Often the roots have not started to grow yet, so it is wise to give a gentle tug or see if you can see any roots growing through the drainage holes in your pot. Fig trees often push out leaves and haven't even started to grow roots.

Thank you for your help!
I left the cutting in the pot and took the glass jar off. It seems to be doing fine, growing 4 very small leaves. It is still pretty small though. The air root grew all the way to the soil level and into it. I gave the cutting a gentle tug and it definitely doesn't want to come out, though I do not see any roots coming out of the bottom, but then again, that pot is pretty big.

The cutting is still in vermiculite/perlite mix, should I move it to a potting mix so the new plant can get some nutrition or is it better off developing more and stronger roots in the original mix? Should I feed it? I would really hate to kill it after all this time and work!
I also read that it should not be moved into its permanent location untill next spring. How do I overwinter it? I have a cold frame, would that be a good place? Or can I leave it in its pot and keep it in the house till next spring? I do appreciate your help. I am very new to this.
Grow