|my lawn had round yellow patches last year. this year it's almost dead with some green areas with a lot of weeds all over.should I spray weed&grass killer and till the and spread bermuda grass seed|
|I think you have the right idea! There are a couple of ways to renovate your lawn. You can rototill it up and start all over, or you can rent a core aerator and aerate your lawn, then spread some sand or compost over the area and reseed.
If you decide to redo the entire lawn, start by rototilling the area to break up the soil. Remove any debris (stones, sticks, weeds, etc.) and then spread 4-5 inches of organic matter over the area and rototill it in, then rake the area smooth. Sod produces an almost instant lawn because the grass is mature with a healthy root system. After laying the sod and watering it down well, it only takes a week or two to become firmly established. Seeding takes a little longer, but the results are eventually the same - a lush, thick, healthy lawn. Once this is done you can reseed your entire lawn.
The second option is to aerate your existing lawn. A core aerator will remove one inch by three inch plugs from the lawn. Leave the plugs on the lawn and they will dissolve in rain or water from the sprinklers. After aerating spread a thin layer of sand or compost over the area and water it in well. The sand or compost plus the soil from the plugs will work their way down into the holes left by the plugs. You can then overseed your entire lawn.
Either approach should improve the soil beneath the lawn and help your lawn grow lush and thick, which will help crowd out any future weeds.