I live in the Cincinnati Oh area and I'm not stuck on Bluegrass, I just want the best lawn, deepest green, and thickest in the neighborhood. I thought Bluegrass was the benchmark. I know the KY 31 TTTF is not the blade I want.

That's odd, I have Cincinnati, OH listed as Zone 6a/6b (you're right on the border).

Regardless, Ohio is completely compatible with bluegrass if that's what you want. You may or may not.

Personally, I consider bluegrass to be the grass against which all others are measured--and found deeply wanting. But that's because I'm willing to put in the time and effort to optimize performance. And money, let's not forget the money.

Bluegrass has absolutely terrible drought resistance, but phenomenal drought tolerance. Or, it wilts quickly and has to be watered, but survives drought very well by going dormant and simply waiting it out.

It's the most demanding of the northern grasses in terms of feeding, and really objects if you give it less than 4 pounds of nitrogen per thousand square feet per year, delivered just the way it likes it (small amounts in late spring, large amounts in fall).

In terms of disease and insect resistance, it's about average. However, planted as a single species (a monoculture), any disease it's susceptible to will run rampant. That's why we suggest multiple cultivars with different resistances to counter that. Planting a single cultivar (a monostand) is asking for trouble (but it can be done).

Properly managed, it's an intense green with blue overtones (mine throws blue topaz highlights in sun that, regrettably, don't photograph at all well), a strong grower, and capable of filling in any holes without much additional encouragement. It feels like carpet underfoot.

Improperly managed, it's a sickly yellow-green, grows weakly, and gets patchy. Just like any other neglected grass.

Plantings are slower to develop than other species, and sprout far slower than most others, so you have to keep after the watering on the seed bed for far longer.

If that's what you want, and you're willing to put in the effort, I'd suggest Midnight II, Prosperity, and Moonlight SLT cultivars for you if you want the darkest colors and excellent performance. Award and Bedazzled are two other suggestions, but the Bedazzled won't be quite as dark a green.

If the idea is kind of daunting, fescue and ryegrasses are easier to manage but do require occasional overseeding in fall.

I agree with Morpheus. Wait until late summer/early fall to plant seed. The grass you plant in the spring will not have sufficient roots to survive the summer. Until then you can work on improving your soil. Get a soil test and see what nutrients may be lacking. Anything you can do now to improve your soil will help the grass when you plant in the fall. In the summer you can do the Roundup. You should spray to kill vegetation, then water to try to get weed seeds to sprout and grow, then use Roundup again. All that takes time. That is a large lawn to renovate. Maybe you should focus on doing just one section this year, see how it goes, then do another section in 2016, etc. TTTF is not the same as K31. You can also use the time between now and the fall to research what seed you want. If you just can't wait until fall, laying sod is an option.

Zone 8 is pretty deep in the south. Must be a typo.

If you live in Cincy and want the nicest lawn in the neighborhood, listen very carefully to morpheuspa. He never posts pictures of his lawn...but I do. Here's his lawn from several summers ago...

If you want to buy the best seed, you need to look for gold tag certified seed. Once you decide on which cultivars you want, you can then search online for vendors who carry that seed. That can be an adventure in itself. You may need to contact the seed producers to see where you can buy the seed. More than likely you will buy the seed online and have it delivered. As for which cultivars, Morpheus gave you some suggestions. I have TTTF, so I don't know a lot about KBG cultivars. I have read that you should select a cultivar from each of three categories: compact, compact midnight, compact america. You can look up NTEP tests for your area to see how particular cultivars tested.

Here is a list of seed suppliers;

http://bestlawn.info/home/faqs/78-2009-grass-seed-supplier-list.html