When I germinate a seed for a hempy bucket I plant it in a peat puck for a few days till it sprouts up. Then you can put that in the hempy.
If you just put a germinated seed in the top of the perlite it has a risk of drying out and dying. Unless your there to mist it constantly. 100 % perlite will wick great but the top can dry out fast in warmer conditions. I like to cut my media with some Vermiculite. It helps to hold water in the root zone.
As for nutes. You give them nutes with every watering. Which should be every other day or so. Full Strength on Vegging and Flowering plants. Maybe 1/2 strength for seedlings and day old rooted clones. Feed more or Flush as needed.