How long do I need to leave weeds sprayed with glyphosate before digging them into the ground and laying turf?

I have a very weedy lawn area. I want to strim it, then spray glyphosate to kill these weeds, then I want to cultivate it, rake it, fertilise and lay turf on top. But how long do I need to leave the weeds after spraying? Like can I just spray them and dig them in straight away, and they will die? Or do I need to leave them a couple of weeks until their brown, before digging them in?