As a garden writer I am guilty of giving short shrift to one subject: lawn care. And yet, lawn care is probably the one garden activity practiced by millions of homeowners on any given week during the growing season — this despite their having very little knowledge about how lawns grow. I am one of these millions, believing that any green plant, once neatly shorn, can be called a lawn. Others may mow, fertilize and water, or try to maintain or improve their lawns, but ours is left to its own devices. Our goal is to ultimately have as little lawn as possible, just enough to host a game of croquet or a long table and benches for summer dining al fresco. Even so, this patch will need to be regularly mowed and weed-wacked. This grassy area is bordered on three sides by perennial beds, and nothing sets off these beds better than a deep green, nicely manicured lawn, even if it’s not a hundred percent fine green turf.

I bring up the subject of lawns because in this area autumn is the time when lawns can re-build, repair and thicken up after going through the stresses of summer. Lawns expand their root systems, trying to get to more of the soil nutrients. Blade growth increases as the plants make more carbohydrates to be stored as food for next spring and summer. In autumn, lawn service businesses do their heaviest fertilizing and reseeding. With cooler, wetter weather there are fewer weeds and less disease to contend with. So if they do it, perhaps we should follow suit.

But first, don't start mowing your lawn short just because the weather's turned cooler. Keep the grass fairly high into the early fall. This will help the grass root deeper, thicken up and build up those aforementioned food reserves. If you don’t have a mulching mower, try to double cut any clippings that are matting on top of the grass, or bag them. Bagged grass clippings are great additions to the compost heap. We've seen steam rising from piled clippings on cool mornings, proof of what they'll do to help heat up and break down your compost's brown materials.

Once your lawn’s growth begins to slow down, you can begin mowing shorter, gradually lowering the mowing height so it is 112 inches high or less before winter. Bentgrass lawns can be cut even shorter. Keep leaves from matting on the grass and avoid unnecessary foot traffic or heavy machines when the soil is soft and wet. This compacts the ground, makes ruts and causes future weeds. Stay off the grass when a light frost covers it, as grass is very susceptible to injury at this time. If your lawn is looking a little thin, this is the time for over-seeding. Just estimate the area to be over-seeded so you know how much seed to get, then head out to the local home improvement store or nursery. Either match what you already have growing or introduce something new. Bring a sample of your grass if you don't know what type it is.

Once you have materials in hand, mow the lawn before seeding, then spread seed right over the top of the existing grass either by hand or with a fertilizer spreader. Water very heavily to get the seed off the grass blades and onto the moist soil below. Keep the soil moist by watering every day. Once the seed sprouts, slow down on the watering so it doesn’t rot. If your grass is pretty thin, it's a good idea to top-dress the seeded areas with some good soil or compost after seeding, or use a grass patch mix on it, as mentioned below.

If you just have a few bare spots to fill in, one of the easiest ways to do this is to spread a patching mixture on the bare spots. Commercial mixes sold for this contain seed, some water-absorbent material, and maybe a little fertilizer, but you can make your own grass patch mix. Pour two bags of gardening soil and two bags of sphagnum peat moss into a wheelbarrow. Add grass seed to the mix to obtain about 20 seeds per square inch and mix it in thoroughly. How can you tell if you have enough seed? Pick up a handful of the lawn patch mix and pour out all but about one square inch in your hand. Count the seeds to ensure you have about 20 in this amount of patch mix. Finally, add two cups of grass fertilizer into the mixture and thoroughly stir everything together.

To apply the patch mix on the bare spots, remove any thatch &mdashl; the brown grass roots under the green blades — and discard them. Add shovelfuls of plain garden soil in any holes so they are about 12 inch below ground level. Scratch the surface of added soil or bare spots with a garden rake to loosen the soil slightly. Fill the brown or bare spots with the lawn patch mix to a depth of 12 inch. Step on the mix lightly so it makes contact with the bare soil underneath. Water the patches thoroughly, keeping the soil moist until the grass seeds germinate.

Alternatively, if you have a leaf mulcher and a bin or pile of shredded leaves, remove the dead patch and then apply a layer of the shredded leaves. Top the leaves with loose soil and plant your seeds. This will fertilize your seeds from the bottom up.