If you have a cool-season grass lawn or, like me, an expanse of weeds, miscellaneous grasses and clover, it is time to get to work! Core aeration is the single best practice for any lawn. Aeration reduces compaction, allowing water, air and nutrients to reach the root zone.
A mechanical aerator digs out plugs of turf at 3-to 4-inch intervals. Each plug is about 1/2 inch in diameter and 3 or 4 inches long. Immediately after plugging the lawn, it will look as if every neighborhood dog has been busy. The plugs, which are left on top, decompose in a few weeks, feeding the soil.
Many folks overseed their lawns at the time of aeration. That means spreading grass seed over the existing lawn. Doing this at the time of aeration ensures improved seed/soil contact, vital to germination.
For cool-season grass lawns, a late-autumn fertilizer application is the most important of the year. Nitrogen from this application is stored in the roots leading to a great green-up come spring. Incidentally, leaving the clippings on the lawn throughout the season provides 25% of the lawn's nitrogen needs.
Lawn immediately after aerating. The little plugs are left on top to decompose.
For the adventurous gardener, one could plant the bulbs of very early-flowering ephemerals such as snow drops in the aeration holes, creating a late winter flowery mead. Their foliage will mature before the need to mow rolls round.
The lawn mower was introduced in 1830, allowing ordinary folks to have flat expanses of green around the home. There they could enjoy outdoor pastimes like croquet. It was the craze for croquet that fed demand for an even lawn surface. Back in the day, seed mixes of various grasses and clovers were marketed to achieve this end.
The quest for the perfect monoculture lawn is relatively recent in that it is dependent upon better living through chemistry. The biggest problem with this ideal is that any monoculture is a colossal target for pests and diseases which spread like wildfire through the entire planting.
Do you know that one can earn a PhD in turf? These gurus of grass are employed by our land-grant universities. Thus they are available for consultation should plague or pestilence strike.