When to place seedlings in hydro buckets

A question from a fellow grower:

I have seedlings with roots, first time hydro grower, starting off small… but I need to know how and when to place them from the tray to the hydro buckets, because they are in a peat pod thing, and the net pot looks way too big, and the guy from the hydro store now told me to put a hole in the net pot? I thought it was over an inch of the clay pebbles… could you please tell me what the correct way is so I dont loose my expensive seedlings… thanks…

As soon as your seedlings are showing roots through the starter cube, you can transplant into system.