This summer was tough on lawns, especially those where watering was restricted. Owners of ravaged lawns are wondering what to do now.
First, assess the damage. Are spots and areas truly dead, or did the grass just go dormant? With cooler weather and more water available, dormant grass should be starting to show signs of life. Check the brown areas closely, looking for new grass blades. Once water becomes available, grass that is dormant greens back up within two weeks.
If no green growth is apparent and patches are a crispy, yellow-brown or a grayish color, it is likely the grass is dead. Fall is a good time to reseed or resod those areas, as long as water is available.
Because it takes some grass seed, like Kentucky bluegrass, up to two weeks to germinate, seeding must be done early to allow time seed to germinate and grow mature enough before frosts occur and before water is turned off. The average date of the first hard frost in this area is Oct. 15, so lawns must be seeded in early September. Resodding can be done later in the fall, as long as water is available and the soil is not frozen.
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Water is critical to the success of reseeding and resodding. The soil must be kept moist to enable germination and provide moisture for root growth. If water is unavailable, you will be wasting time and money.
If more than 50 percent of your lawn is dead, consider complete renovation. Get rid of the dead grass and thatch before you reseed or resod. Seed and sod roots must be in touch with bare soil. Do this by mowing as low as possible and then using a rake, dethatching machine, or sod cutter, to remove grass and thatch. Once you have bare soil, apply a starter fertilizer and the seed at the recommended rates on the labels and then rake the seed into the top of the soil.
If 25 percent to 50 per cent of your lawn is dead, complete renovation can be avoided with over-seeding. First, mow a height of 1.5 inches. Then, rent a machine called a slit seeder, or ire a lawn care company. The slit seeder cuts through the grass and thatch and into the soil, dropping grass seed into the slit it creates. If you do this yourself, make two passes over the area in opposite directions. Make sure the seed is planted at least one-fourth-inch deep in the soil, and finish with an application of lawn starter fertilizer and a light raking.
Next, moisture is needed to promote the germination and growth of the seedlings. This can be tricky, because you need to water frequently to keep the soil moist but not too wet. Excess moisture can lead to disease problems. Once the grass germinates and plants develop several leaves, you should water more deeply and less frequently.
For lawns that survived the heat and are still green and growing, fall is the best time to fertilize. Apply fall lawn fertilizer in early September and again in early November.
Marianne C. Ophardt is a horticulturist for Washington State University Benton County Extension.