Maybe counterintuitively, September is the best time to work on your lawn, whether it’s changing your mowing routine or the once-per-home task of planting an entirely new lawn.

Lawns do best in cool weather and often go dormant in the six hottest weeks of July and early August. In my neighborhood in Cape Elizabeth, people who didn’t water their lawns this very dry year had a field of brown in mid-August. But after cooler temperatures and almost an inch of rain over four days of occasional showers in late August, the lawns greened up again. A well-grown lawn will survive a lot of drought.

My wife and I moved to our house 40 years ago this month (it doesn’t seem that long). We didn’t manage to get the lawn seed down until the first week of October. While one of our son’s kindergarten friends sank knee-deep into our would-be front lawn after a heavy rain the following spring, that was the only problem we had. The grass sprouted beautifully in very late fall. And the seed that didn’t sprout in the fall began growing when everything thawed the next spring. Anyway, if you’re planting a lawn, it’s best to do it in the next week or so.

Now, for more routine tasks.

Rake the lawn. It is OK to let the leaves stay in the shrub and flower gardens because they break down and add organic material to the soil and suppress the weeds – even though the leaves also provide homes for mice and voles. Everything is a balance, and you make your choices.

On the lawn, however, the leaves get matted down by rain and snow and smother the grass if you don’t rake them. Raking is better than using a leaf blower because in addition to removing the leaves, it gets rid of some of the thatch that builds up, allowing the lawn to breath and send up new shoots in the bare spots. Besides, the loud, shrill sound of a leaf blower irritates everyone in the neighborhood.

Keep on mowing. Throughout the heat of the summer, I mow with the mower at its highest setting to keep the grass roots shaded and fed from the photosynthesis provided by the longer blades. I lower the setting for the last two mowings in the fall – when I also am bagging up the early-dropping leaves – so the lawn goes into the winter at the lowest height possible without damaging the grass crowns. During this time of cooler temperatures, the grass roots are warmed by what sun is available, and the shorter grass lets more leaves be blown away by fall winds. The chopped-up leaves and grass clippings go into our vegetable garden.

You should get a soil test to see if the lawn has the proper pH and needs any other amendments. If the lawn soil is too acidic and needs lime, adding it in the fall gives it more time to break down.

The Maine Yardscaping Partnership several years ago released a study that said lawns that are more than 10 years old do not need to be fertilized. But if you are going to add a fertilizer, it is best to do it in the fall. Though the blades of grass grow more slowly in the fall, the roots continue to grow quickly. The fall fertilization feeds the roots while enough nutrients stay in the ground to give the grass a boost in the spring.

Use a fertilizer with no phosphorous – phosphorous causes algae in lakes – because most Maine property has more than enough phosphorous already, studies have shown. Our soil test last year confirmed that phosphorous content was above optimum.

Every three or four years, a lawn should be aerated. Over time, the soil where the lawn grows gets compacted – by hard rains, by people playing games or walking around looking at nearby flowers and even by routine mowing. Aeration allows necessary air, water and nutrients to sink into the soil and feed the roots. Core aerators are available for rent at most tool-rental stores. Leave the cores on top of the lawn, where they will break down into a kind of compost.

Except for the bit about planting a new lawn, the preceding paragraphs apply to the care of a lawn that looks pretty good. Now we get into fixing problems.

Any bald spots in the lawn can be reseeded. For small areas, an all-in-one lawn repair mixture works best. If the soil itself is in good shape, just loosen it up and add the mixture, which includes seed, fertilizer and a bit of mulch to keep the area moist. Keep the area watered until ground freezes or snow falls.

A way to improve a lawn where the soil is poor, according to a University of Maine Cooperative Extension publication on low-input lawn care, is to spread up to half an inch of compost or a soil-compost mix over the entire lawn. The mix has to be raked out so the blades of grass are covered at the roots but the top of the blades are above the compost; doing this correctly takes time. Once the compost is spread, it helps to topseed the lawn with grass species like fescues and perennial ryegrass that require less fertilizer and watering than traditional bluegrass-heavy blends. This is another occasion where a good gardener reads labels: The grass seed bag will tell you what it contains.

I spent the afternoon of Labor Day doing those repairs on a sad-looking, heavily used section of our backyard lawn. I’ll let you know how it comes out sometime next spring.

If none of this works, add a lot of compost, till in the whole area and start over.

The lawn would have to be really bad for me to be willing to do that much work.

Tom Atwell is a freelance writer gardening in Cape Elizabeth. He can be contacted at 767-2297 or at: tomatwell@me.com