My neighbor’s lawn comes through every winter green and thick. Mine came through looking like a threadbare rug. For years I blamed the soil, the weather, the whole neighborhood. Then one September he told me the difference was not what he did in spring. It was what he did in fall.

Grass builds its roots in September. Help it then and it shrugs off winter.

Keep Mowing, Just Lower

Do not stop mowing when the weather cools. Keep cutting until the grass stops growing, and drop the blade height for the last few mowings. Grass that goes into winter too tall flattens under snow and mats. Grass that is too short loses its roots. Two and a half to three inches is the sweet spot.

Feed It Now, Not in Spring

September is the best time of the year for fertilizer on a cool-season lawn. The grass is growing, the roots are storing energy, and the weeds are slowing down. I use a slow-release fertilizer and water it in.

I skipped this for years and always wondered why my spring feeding never caught up. It was too late by then.

Water Deep, Less Often

In September, water deeply once or twice a week instead of a light sprinkle every day. Deep watering pushes roots down, and deep roots survive winter. A light daily sprinkle makes shallow, weak roots that freeze out.

Clear the Leaves

Rake or mow the leaves before they pile up. A thick wet mat of leaves smothers the grass all winter. I mow mine into the lawn with a mulching blade, which feeds the grass as it breaks down.

• Aerate if your soil is compacted, early fall is ideal
• Overseed thin patches now so they fill in before frost
• Keep walking traffic off the lawn when it is wet

That September routine cost me an afternoon a week. It paid for itself by April.