The Future of Your Lawn Is Now: Tending Grass in the Fall

When managed properly, a lawn can slow rainwater, allowing it to percolate into the soil and reduce sediment and other runoff into rivers and streams. Healthy lawns control dust, dissipate heat and noise, reduce glare, lower fire risk, and can improve soil and water quality.

Now is the time to stimulate a strong network of roots and top growth on lawn grasses. The varieties typically grown in the Washington region are cool-season grasses. They thrive in moist, well-drained soil and should be in six hours or more of sun.

Here's how to keep your grass green, thick and healthy:

Mowing

Mow regularly, cutting no more than one-third of the blade height. Cutting too much shocks the grass and makes it take longer to renew between mowings. Set mower for 3 to 3 1/2 inches. Taller blades of grass allow less weed competition and have more leaf surface for photosynthesis.

One common but incorrect mowing practice I have seen on cool-season turf is cutting a lawn as low as possible once or twice a year for rejuvenation. This doesn't make it stronger. If areas are scalped when mowing by using a low blade height, bare spots in the turf are exposed, and crabgrass and broadleaf weeds can get a foothold.

Pick the right mower. Choices include gas, manual push and electric. Push and electric mowers are more environmentally friendly because they reduce emissions.

Keep the blades sharp. Dull blades tear grass and cause browning.

Make proper use of falling leaves. Mow autumn leaves that fall on your lawn into tiny particles; they help fertilize. If leaves become thick, grind with the mower or take them to the compost pile. If matted on the lawn, they can weaken and kill grass. Keep heavy accumulations of leaves off the lawn, and continue mowing until growth subsides, in November or December. This greatly reduces the chance of the lawn having snow mold or other fungal diseases.

Aerating

Enrich the soil under your lawn by aerating with a core aerator, available from equipment and tool rental companies. It must be the type of machine that removes plugs of soil, not one that just punches holes. Go over the lawn three or four times. Soil should have some moisture for the aerator to penetrate properly, but never aerate when the ground is soggy.

Have the soil tested at your local garden center, or get assistance from your county cooperative extension service before amending the root zone with compost or fertilizer. This will alert you to shortages in nutrients and record the pH.

Spread compost, an integral part of the aeration process. Sprinkle it into the aeration holes, but do not cover the blades of grass. If compost is fine-textured, use a broadcast spreader. Otherwise, sprinkle it with a shovel or by hand. Commercial compost products, such as Leafgro, are fine-textured enough to use in a spreader and will fall through the grass blades and into the soil. Your own organic material will work well if it is dry and powdery enough. After a couple of years, compost alone will make the lawn thick and green, without need for supplemental fertilizer.

Fertilizing

Lay fertilizer over the soil surface after aerating and sprinkling compost, to help it get to the roots. Use a broadcast spreader as long as you're sure that the material contains no weed killer.