You can buy these rolls of fiber that have seeds embedded in them, along with fertilizer etc. You roll them out, sprinkle with a light earth cover and water. The fiber keps birds off and mainatins water and resists rain washouts.
glance through these. Of course, you are limited to the grass biologically limited growth rate.
https://www.google.com/search?q=grass+seed+rolls&oq=grass+se...