Posted: 25/04/2017 at 14:17
My OH scarifies when he feels like it which can be early or late and depends on weather conditions more than anything. If you've already mown this year and it isn't freezing or soaking wet then go ahead. You'll end up with a scruffy looking mess but it will recover.
If you have a lot of moss then yes, go ahead and aerate by poking in your garden fork deeply and at frequent intervals then wiggle to widen the holes. Brush in some sharp sand to maintain the holes for drainage and aeration of your grass roots then feed with a lawn feed.
The most important thing you can do is to make sure you don't scalp your grass. Maintain the mower blades at a minimum of 1" high and higher in dry or cold weather so your grass has enough leaf surface to feed and maintain a strong root system that will help it fight off competition from moss and weeds.