You have a choice ahead of you. Do you want to lay down seed or sod? There are pros and cons to each.
How soon you can plant seed depends on the type of weed treatment you choose. Pre-emergent herbicides will prevent grass seeds from growing just as much as weed seeds, so it would be no good to sow seeds immediately after.
To prepare the soil after either method, make sure you till it down to roughly 6 to 8 inches.
Step 5: Rake and Till
Weeds come in multiple categories, either broadleaf, grass-like, or grassy.
Always set the spreader to half the recommended drop rate and spread the seed in one direction, then one or two more in different directions to make sure the coverage is nice and even. You don’t want your lawn to have weird patterns or stripes.
Aerating your lawn can help break up thatch, the layer of decomposing organic matter between your lawn’s soil and grass blades. Thatch can be beneficial, since it can make your lawn more resilient and provide insulation from extreme temperatures and changes in soil moisture. But if it gets over a half-inch in thickness, it can cause root damage, including root rot.
Aeration improves your grassroots’ access to air, nutrients, and water. Use a spike or core aerator to break up the soil. If you use a core aerator, be sure to make two to three passes in different directions. Allow the plugs of soil you remove to decompose on top of your soil layer rather than remove them.
If you have had a dry summer with below-normal rainfall, you need to replenish soil moisture before preparing a seedbed. Give the entire lawn a thorough watering, soaking until water has penetrated to a depth of at least 6 inches, then allow the surface to dry for a day or two before starting soil preparation.
The best time for lawn renovation throughout the U.S. is mid-August to mid-September. Most weeds have not yet dropped their seeds and there will be little new weed growth. Also, reseeding at this time will give the new grass a chance to establish itself before going dormant for winter. Get rid of the weeds by manually pulling up large, spreading weeds. Follow up by applying a selective herbicide product that kills common broadleaf lawn weeds while not harming grass. For tough grassy weeds, like quack grass or crabgrass, use a nonselective herbicide such as glyphosate on the spots where these weeds have established themselves. Normally, all weeds will be dead within two weeks. Apply another herbicide dose in three weeks to get newly sprouted weeds.
Most deteriorated lawns have a built-up layer of dead and partially rotted grass stems, roots and rhizomes just below the green grass leaves. This is known as thatch, and it must be removed before reseeding so water and fertilizer can reach the new seed. For small lawns, you can remove thatch with a garden rake. For large areas, go over the lawn with a power dethatcher, also known as a vertical mower or power rake. These machines can be rented from garden centers. Remove the clumps of matter left by the machine with a garden rake and level the soil by raking it.
Water the Site
If you are faced with a neglected lawn that’s partially dead and is being taken over by weeds, you may be able to renovate it. Restoring a deteriorated lawn may be possible if the weeds and dead spots cover less than 40 percent of the lawn area. Renovation of a weedy lawn involves more than just mowing down the weeds and throwing some grass seed over the lawn.
The soil nutrients most important to healthy grass plants are nitrogen, potassium and phosphorous. Supply these nutrients by applying a commercial fertilizer formulated for starting lawns and lightly rake it into the soil before you reseed. Buy a grass-seed blend suited to your climate and local conditions and spread it over the lawn with a drop spreader or rotary spreader. Absent a different recommendation from the grass-seed grower, spread the seed at a rate of 2 pounds per 1,000 square feet on a lawn with substantial plots of live grass and 3 pounds per 1,000 square feet on bare soil. Water lightly once or twice a day to keep soil moist but not sopping wet. Don’t mow until the new grass gets 3.5 inches tall.
Herb Kirchhoff has more than three decades of hands-on experience as an avid garden hobbyist and home handyman. Since retiring from the news business in 2008, Kirchhoff takes care of a 12-acre rural Michigan lakefront property and applies his experience to his vegetable and flower gardens and home repair and renovation projects.
You don’t have to till your lawn, and you don’t have to tear it up for over-seeding a lawn to be effective.
I like to spread some quick-release starter fertilizer on the lawn before spreading my seed. Scott’s makes a really good product (Amazon link), and it’s particularly good for Spring overseeding because it has a crabgrass preventer in the mix.
How Overseeding Can Help Your Lawn
If your lawn is thin, and you want it to grow in thicker to prevent weeds from growing, early spring is your better bet.
For new grass, water lightly twice per day for the first week, and water more heavily the second week.
The hot summer months are very harsh for new grass seedlings, so springtime isn’t quite as good for most weedy lawns.