About a week, 2 at most depending on environmental factors.

Tall fescue takes two to three weeks, on average, bluegrass takes about a week to ten days, same for creeping fescue, and about 5-7 days for perennial ryegrass. Cold weather slows that down, while moderately warm weather can speed it up. Really hot weather can prevent sprouting, though.

Germination is quicker in warm moist conditions and slower in cold or hot dry ones.