Our lawn had become very patchy and hay-like, so about a month ago, we dug out all weeds and moss, raked all the dead grass off, and threw some seed down. After a fair bit of rain, there is definate improvement, although I would say more a revival of the old grass rather than the seed taking particularly well. If we do this again a few times through the summer, is there likely to be significant improvement, or if there something else we need to do at a different time?