CORVALLIS, Ore. – Fall is a good time to renovate your lawn, especially if you conserved water over the summer.
That toasty carpet in your front yard will come back to life with cooler temperatures and the first autumn rains, according to Robert Golembiewski, Oregon State University Extension turf grass specialist. As turf comes out of dormancy, you can see which areas need to be renovated.
Golembiewski has advice to help homeowners treat their drought-stressed lawns.
Fertilize the lawn with the onset of the rainy season to maximize re-growth of dormant turf, he suggests, and then reseed where turf needs a boost. Water-soluble fertilizers (those containing ammonium sulfate or urea) are a source of rapidly available nitrogen and result in a quick green-up of the turf. As a general rule, apply one to one-and-a-half pounds of nitrogen per 1,000-square feet of lawn to encourage regrowth of weak or thin turf.
Selecting a grass seed mix for reseeding is a personal choice based on how the lawn area will be used, drought resistance and other considerations. In western Oregon, perennial ryegrass is a common choice because it is quick to establish and has better than average drought tolerance.
"Avoid seed mixes that include annual ryegrass," Golembiewski said. "Annual ryegrass grows vigorously through winter, but doesn't blend well with other grasses, and dies out in mid summer. In essence you get nothing but extra work and an ugly lawn for your trouble."
Watering the reseeded areas is essential to good establishment. If fall weather turns warm and dry, you may need to water a few times a day to keep grass seeds moist. After the green shoots are visible you should be able to cut your watering in half, and by two weeks you should water only every three to five days if needed.
Mowing is an important step in the process, even in the fall. Mowing stimulates the turf to begin filling in. An occasional mowing during winter might be necessary to keep the turf healthy, dense, and vigorous.
Dethatching may be necessary, but is best done in the spring when the turf begins vigorous growth. Turf can be dethatched in the fall, but is more susceptible to weedy invasion of annual bluegrass and other undesirable invading grasses and winter germinating weeds.
"The typical home lawn in western Oregon is an evolving ecosystem that gets more complex each year," Golembiewski said. "At first, it consists of one or two species of grass found in a typical seed mix. Over time, it evolves to three or four species that were not part of the original seed mix but are well adapted to the environment. We call this mix of species a 'climax' lawn."
The conversion to a climax lawn is a natural process. The end result is a lawn adapted to your growing environment, according to Golembiewski. It may need less fertilizer and should be mowed shorter than commonly planted turf grasses.
All lawns, either newly planted or renovated, need care year-round, and the OSU Extension Service has an online guide to help homeowners with year-round lawn care: "Maintaining a Healthy Lawn in Western Oregon," EC 1521.