When can I put this spout in hydroton?

I have a little DWC setup, and I have a couple sprouts going. I was wondering when I should move the sprout into the hydroton? It's in a peat pellet, and it's been looking pretty good so far! I do have a little 2" net pot too. Any advice for how/when to move it over would be much appreciated! Thanks!

you wanna move it over asap,, once i see the first leaves forming ( not the water leaves ) i switch them over.