The heat of summer has probably taken its toll on your lawn. Fall is a good time to renovate troubled patches in your lawn, especially if summer drought has turned it to a toasty brown mat of dormant grass. Lawns in the foothills will be coming back to life with the cooler temperatures and the first rains of autumn. As your turf comes out of dormancy, it is easy to see areas that need special attention.
Start by fertilizing the lawn with the onset of the rainy season to maximize re-growth of dormant turf. Apply water-soluble fertilizers (those containing ammonium sulfate or urea) with a source of rapidly available nitrogen to stimulate a quick "green up" of the turf. Use a balanced, complete fertilizer like 15-15-15 (N-P-K). As a general rule, apply 1.5 to 2.0 pounds of nitrogen per 1,000 square feet of lawn to encourage re-growth of weak or thin turf. It may be best to make two applications a few weeks apart with half of the total amount each time.
Once your grass has greened up, it’s time to reestablish the areas that are patchy or dead. First, roughen or rake up the patchy or bare surfaces, remove plant debris, then reseed. Apply a thin layer of mulch over reseeded areas. 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 the foothills, tall fescue is an excellent choice.
Avoid seed mixes that include annual ryegrass. Annual ryegrass grows vigorously through winter, but doesn’t blend well with other grasses and dies out in midsummer. It also has the nasty habit of crowding out better grass species. Vigilant watering may be essential to sound establishment of the reseeded areas. 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 may cut watering in half, and by two weeks water every three to five days, if needed.
Mowing is an important step of early fall renovation, as well. Cutting the grass stimulates the turf to grow more and begin filling in the sparse areas. An occasional mowing during the winter might be necessary to keep the turf healthy, dense and vigorous. Lawns are mini-ecosystems, in a constant state of change, just like any other plant community. The typical home lawn in the foothills is an evolving ecosystem that gets more complex each year. 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 of a newly planted patch of grass to a climax lawn is a natural process – a kind of plant succession. The end result is a lawn adapted to your growing environment. A climax lawn may need less fertilizer and should be mowed shorter than commonly planted turf grasses. Mature climax lawns perform best when the mower is set to about 1½ inches.
This article adapted from Cooperative State Research, Education and Extension Service, USDA. Please contact the Farm Advisor’s office at cecalaveras.ucdavis.edu or 754-6477 with your agricultural questions.