CORVALLIS, Ore. – Grass lawns are the default for most yards, but some people want other options, like edible or ornamental landscaping, mulch or low-maintenance groundcover.
"Maybe you have a lawn full of difficult-to-control weeds like annual bluegrass or rough bluegrass and you want to start over," said Alec Kowalewski, turfgrass specialist with the Oregon State University Extension Service. "Or you want to switch from grass to lawn alternatives like groundcovers."
In either case, you'll need to first remove the existing grass. Kowalewski offers two main approaches: an organic technique that uses no pesticides and a chemical method.
The organic method begins with placing plastic sheeting on top of the grass. "You need something that will totally stop the gas exchange of the atmosphere," Kowalewski said. "You're essentially suffocating the plant." In the heat of summer, it could take two to three weeks to kill the grass.
The conventional method is to spray a non-selective herbicide such as glyphosate on the grass in early morning and away from other plants. Apply again two weeks later to kill any dormant weed seeds that may have germinated. Alternatives to glyphosate includes organic, OMRI-listed products with vinegar or acidic acid. When applying pesticides, regardless of what type, always wear protective clothing and follow the instructions on the pesticide label carefully.
No matter which method you choose, Kowalewski recommends scalping down the dead grass with a mower when it turns brown and then aerating the lawn.
Since living root parts might still remain underground, it's wise to completely remove any sod as well. A hand- or gas-powered sod cutter can be rented to separate the sod from the soil. Adjust the blade depth to ¼ to ½ inch. Afterward rake up sod manually with a square shovel or pitchfork.
Throw discarded sod and grass in the garbage or compost it. With the old turfgrass successfully removed, you're ready to establish your new landscape.
If you prefer to keep you lawn but it needs some help, turn to the Extension guides Practical Lawn Establishment and Renovation, Practical Lawn Care for Western Oregon, and the thorough video Integrated Pest Management for Turfgrass.