|How can I obtain a lawn that is desease free and is full of grass, with no thinning patches.|
|A healthy, lush lawn needs good, fertile soil. Rather than tearing up the existing grass and laying down sod or reseeding, you would benefit by addressing soil concerns first. I would begin by having a soil test done, to see just what shape your soil is in. Clay soil is often acidic; the soil test will tell you the pH and, if necessary, how much lime to spread. Clay soil is generally high in nutrients, but compacts to form an impenetrable surface, and it often remains soggy during wet spells and dries to a hard, cracked surface. Few plants can survive in such soil. The addition of organic matter improves heavy clay soils; your plan of action really depends on how much you want to spend. You could have the entire area tilled up, adding lots of compost and manure. You could spread a layer of topsoil/compost over the entire lawn, and reseed. These are all quite expensive options. You might also try spreading a thin layer of compost over the entire lawn, let the existing grass sprout up through it, and reseed bare spots. If you can continue this practice over several years, you may be able to build up the organic matter in the soil sufficiently to support a lawn, without a huge capital investment. If you can aerate the lawn before spreading the compost, using either a hand-held (or shoe-mounted) device, or rent a gas-powered machine, you'll go a long way toward providing a better soil environment. If the soil test shows that the pH is way off, then annual applications of lime and compost or other organic matter may do the trick--though it will take a few years.
Once you've got some healthy soil, you can keep your lawn healthy with deep waterings once or twice a week (depending upon weather), regular mowing, and a regular feeding schedule: April, June, September and late November or early December. Your local Home Depot will have the right fertilizers on sale at just the right time to apply in your gardening region.
Best wishes with your lawn!