Make the lawn autumn/winter-proof

Of course, it depends on what your lawn looks like and whether there is still any grass left. However, it is now too late to apply normal nitrogen fertilizer, it will get cold soon, and the lawn should not grow so much anymore. [Herbstrasendünger] contains a lot of potassium and protects the grass from frost in winter. I would mow the lawn very short in spring, then scarify and reseed with a starter fertilizer. Then it would be ideal to spread a very thin layer of soil (half a centimeter) on top. Now you have to keep everything constantly moist until the lawn has grown nicely. If you mow regularly (at least once a week, preferably twice) and apply some fertilizer every four weeks or so, the lawn will grow nice and dense. For fertilizing, I have a battery-powered "handheld device" from which the fertilizer shoots out at the push of a button. That makes fertilizing super fast and really fun, and above all, the lawn doesn’t burn anywhere, as often happens with those fertilizer spreaders (which you pull behind you).

Best regards
Sabine

Does it mean not to scarify and fertilize at all in autumn?

If you now have a proper meadow, then your former lawn no longer has the right grass species, but weeds. If you now scarify and fertilize, no grass can grow where there is none. Therefore, you definitely have to reseed, and it is now too late for that, grass does not grow in winter. If you scarify in spring, the grass seed can germinate and take root nicely because the soil has been loosened a bit. Grass seed always consists of several types of grass. There are more resilient ones that do not grow as beautifully and densely and fine, nice grasses, which, however, are not as durable. If you have not taken care of the lawn at all, now you only have the most resilient grass species left, and the other types have dried out or starved. That is why I would definitely reseed fresh, so that the lawn becomes really dense.

Best regards
Sabine

That's why you definitely have to reseed fresh, and it's too late for that now; grass doesn't grow in winter.

You can sow new grass AFAIK from 5 °C. It's also not bad in autumn, because the next long hard dry heat period is still a long way off ;-). However, I don't want to say anything specific about the case; it might be better to wait until spring (but then the "weeds" also grow).

Maybe one can already, but it's not optimal. It should definitely not be colder than 10 degrees. Ideally, it is warmer than 15 degrees. I would rather not invest in expensive lawn seeds if it might snow in four weeks. If you fertilize properly, the weeds don't stand a chance.

Best regards
Sabine

We will still sow now (that is, during October). The prospect of usable lawn from next spring is worth the (small) risk. (Small, because it only costs 1 Euro/m² ...).