How long till I can mow?

[Tx Redneck]

We had a large area redone with compost and then hydro-seeded. Most of the seed is growing in, but I also have a lot of weeds growing in as well that are getting tall. How long does the newly seeded grass need to grow before I can mow? We also added more seed via spreader to fill in the bare spots and hopefully choke out some of the weeds.

The spreader seed w put down yesterday, but I was gonna wait till I'd watered and everything was moist and sticking to the ground before I tried to mow.

Thoughts?