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My Lawn has some spots of disease and several kinds of grass, which are ugly. What is the best way to kill off these problums and start a new lawn.
- Oakland, OR
It all depends on the extent of the disease and/or damage. Brown spots, for example, can be caused by overuse of herbicides, improperly applied fertilizer, dogs relieving themselves on the lawn, or even sod webworms, which are the grub stage of lawn moths. In order to properly treat the lawn you need to know what the disease is or what is causing the damage. If the problem is sod webworms, then the solution is a multi-attack, starting with beneficial nematodes such as Steinernema feltiae or Steinernema carpocapsae, or Bacillus thuringiensis (Bt is a bacterium that targets only caterpillars). If the cause is due to overuse of fertilizer or herbicides, watering deeply and thoroughly will help flush the excess out of the soil.
As for starting a new lawn, it may be best to reseed the affected areas. The best time to do that is now (in fall) or in early spring. First, create a find seedbed by loosening the soil to a depth of at least 4 inches, then level the soil with the back end of a rake. Mix equal amounts of compost and sand together and spread a thin (1 inch or less) layer over the bare areas. Now mix your grass seed with additional compost or a slow-release lawn fertilizer and evenly distribute the mix over the prepared seedbed using a hand spreader. Firm in the seed by gently tapping or pressing the surface with the flat end of the rake. The key to getting a higher germination rate is to create a good seed-to-soil contact. That said, covering the newly seeded area with an additional 1/8 to 1/4 inch layer of seedling mix or light compost will help accomplish that goal. Finally, water the area thoroughly and keep the seed bed slightly moist at all times until grass seedlings are established.
Ultimately the best defense against any lawn problems or issues is to do things that help foster a healthy, thick turf. And you can do that with proper feeding, watering deeply, aerating regularly, and mowing high and mowing often. Good luck!