Posted: 04/03/2015 at 11:59
Patience! Grass isn't going to improve over the winter months but at least the scarifying and autumn treatment will help it not get worse.
Grass starts growing again when temps get to 8C so wait another month to sow new seeds when it will be warm enough for them to germinate and grow. Until then, keep the grass cut to about 2" when it does start growing so there is enough leaf to feed the roots and make them stronger.
As the grass thickens up in the warmer weather you can cut it down to 1.5" which will help it deal with drought in dry spells. Any shorter and you will leave it weak and open to competition from weeds and moss. Spring and autumn scarifying should be done before sowing any new seed.