New lawn - fertilizer? grub control?, etc,

[cliff27]

Had lawn hydroseeded (Rhode Island; fescue and annual rye with 10% kbg) 3.5 weeks ago. Supposedly had starter fertilizer and crab grass preventer. Grass has come in but with fair amount of crabgrass. Also, seems to be growing slowly , about 1 inch in most spots.

Can I put down fertilizer this soon? Use a starter instead of regular?

[RigglePLC]

Use a fertilizer designed for turfgrass. Make sure if has a genereous portion in the slow release form. Feed it about once a month until the new grass is thick. It will be gradual steady progress. The crabgrass will be bad, but frost will kill it in October.