Oops. I meant 'scarifying lawns' in the first subject line not scarififying!

If there is more moss than grass, and you remove the moss, then the lawn will look pretty awful, at least for a while. It is a little late to be reseeding now, and if you leave bare earth without also aerating then the moss will be back by spring. Wait until spring if you need to do major work, perhaps just aerate now.

If you have more grass than moss, it will still look pretty awful when you finish scarifying. I find, despite the standard lawn advice, that scarifying in the autumn just leaves bare earth for the moss to colonise over a wet winter. Scarifying in spring leaves bare earth which the grass colonises because it is growing so fast at that time of year and the surface of the soil dries out between showers. That at least is my experience in the north west of England.

I only just noticed this post. Mid-September would not have been "a little late to be reseeding" here in the south of England, it would have been absolutely the ideal time. On account of the shut-off in June and July, and the very mild autumn, lawns have been (and are still) growing like billyo, needing a good cut every week. I sowed some patches of lawn a couple of weeks ago and they are coming up fine. Autumn will not begin until November this year, it seems.

Depends where chopjuice lives. Much of the country is still in a marine climate with adequate water throughout the year, despite the bombardment of information about mediterranean gardening from journalists and gardening gurus based in the home counties. *sigh* :)

Yes, shrubs'n'bulbs, we seem to be living in completely different climates, horticulturally. So much for applying the zone system here (we've both put 8-9). The Mediterranean characteristics of the climate have been exaggerated. The reason for the drought was not the hot summer (we had loads of rain in May and August) but the very dry and reasonably cold winter right up to the end of March. Spring happened very rapidly in April, then we switched straight over to a very long summer. The Mediterranean aspects are the shut-off in mid-summer and the warm Indian summer/early autumn. Plants (including lawns) have simply been catching up. I thought they mostly had some kind of trigger which switched off when light levels or daylight hours fell below a certain threshhold, but apparently not - and certainly not grass.