From the ground up: Should you start new or repair an established lawn?

Fall is the optimum time to start a new lawn from seed. The warm days, cool nights and fall rains encourage rapid growth. Plus, fewer weed seeds germinate in the fall, so you'll have fewer weeds in your lawn.

To start a new lawn, prepare the soil to be seeded by tilling, spading or raking to a fine texture. Optimum soil depth should be 6 inches. Bringing in additional topsoil and compost may be necessary, mixing thoroughly.

Evaluate your location. Is it shady, sunny, flat or at a slope? Sunny area means it receives at least six hours of sun daily. Kentucky bluegrass does well in sun but is slow to establish, so ryegrass seed often is included in the mixture to help the bluegrass get established.

If it's shady, fine-leafed fescues are the seeds of choice. If your lawn is a combination of shade and sun, a mixture of bluegrass and fescue is a good mixture with each seed type dominating in the proper area.

A starter fertilizer high in phosphorous (the second number in the NPK analysis) may be applied to the area immediately before seeding.

If seeding a large area, a drop-type seeder may be used, or in a smaller area the seed may be broadcast by hand. After the seed is sown, lightly rake the area, but seed left above the ground has a better chance of germinating than seed planted too deep.

The area should be lightly mulched to help conserve moisture. Use clean straw or grass clippings with no pesticides or herbicides applied. Mulch sparingly so you don't smother the seed. Ideally half of the soil should be visible through the mulch. If the area to be seeded is on a steep slope, erosion control mats can be purchased at garden centers.

Water is the next and most important step. Water gently so seed doesn't wash away. Water daily, keeping the upper 1 inch of soil consistently moist. In hot, dry, windy conditions, it may be necessary to water twice a day. Never let the area dry out.

When seedlings are 2 inches tall, water less often but more deeply. If there are weeds in your lawn, don't apply herbicide until six weeks after seeding. Mow the new lawn at a 3-inch level.

A frequently asked question is 'how do I get grass to grow under my trees?” Grass doesn't grow under trees. The best thing to do under a tree is to put down mulch. The mulch should be applied out to the drip line, which is the edge of the widest part of the tree. Tree roots will be kept cool and the tree will thrive.

For more lawn questions, call the Linn County Master Gardener hotline at (319) 447-0647.

' Judy Stevens is a Linn County Master Gardener.