Once six weeks have elapsed, you could put some seed down - but by then, it'll be November I expect, so it might not take.But grass seed is cheap, so you could give it a go if its mild and just redo it in spring if it doesn't work.

Bear in mind you need to scrape up the top inch of soil to get a fine tilth, tamp it down with the back of a rake, then sow the seed - it needs something loose and friable to root into.