I'm not sure I'd take the time to bother :-) Grass seed sprouts perfectly well on its own in our cool, damp PNW springs. I'd just overseed the bare spots and call it good! Or you coud try making your own hydroseeding slurry, but adding some cellulose fiber would help with both a more even dispersal and for seed protection.

I think my primary concern would be damaging or even destroying those tiny little new roots when it came time to spread on your bare spots. Let us know how it goes.

What aspects of the process appealed to you?

Where did you see it “done”?

It’s appealing because, despite the rainy climate, I have trouble with my seedlings sprouting. Here’s one of the links: https://www.hometalk.com/30045425/how-to-make-grass-grow-fast-fix-bald-spots