What type of grass do you have?

If it is mostly a weedy mess, you are best off killing everything and starting over. Roundup is the way to go for that task. Spray it all, wait a week, spray anything green, wait a week. Cut it as short as possible and rake up the debris. After that, you can seed, fertilize and water,water,water. If you start the process in 2 weeks or so, you will be ready to reseed at the end of august.

Bestlawn,

I'm not sure what kind of grass it is/was. My father-in-law thinks it's fescue with some weeds mixed in. I have to mow it at least once a week it grows so fast and tall and thick.

Billl,

If I kill it all off now, will it start growing again if I wait until late September to seed/fertilize? If I do like you said, once I rake it all up can I use a seeder slicer to put down the seed? What kind of fertilizer do you suggest? I've also seen posts of people using Nitron A35 as well.

Thanks guys.

This site can help you identify the grass. You want to examine the leaf blades very closely. Or take samples with roots to your nearest K-State Cooperative Extension Service. They can identify the grass type for you. You need to know what type to grow.

Don't bother killing anything until 2 weeks before you are ready to reseed. If you do, you just give more weeds a chance to start growing and you'll have to do it again.

A slit seeder would be fine. If the areas isn't too large, you could get away with a good raking to break up the top layer of soil. Otherwise a slit seeder or aerator works well.

Fertilizer is up to you - prefer organics. If you go with an organic, apply it when you start killing weeds because they take a couple of weeks to do their stuff. If you use a synthetic (scotts etc) get the one labeled as "starter" fertilizer. Use that when you seed and follow up with a standard lawn fertilizer (no weed killer though) about 4 weeks after the grass starts growing.

For Nitron - mostly I think it is snake oil. It is a surficant, so it lets water penetrate the soil more easily. That is certainly a good thing, but baby shampoo or dish soap will do the same thing. If your soil is compacted though, I would recommend aerating over any of the liquid aerators. Since you are redoing the lawn anyway, you can run the aerator over the whole thing a bunch of times and tear it all up without worrying about it looking bad.