Unfortunately darkest green doesn't equal the best choice. Charlotte is tall fescue territory (if you want a cool season grass), but the darkest one is not the best performing one for your area. One of my favorites, that is dark green, and does really well in the transition zone is Bullseye. If you want to see the results of all the TF cultivars then go here: http://www.ntep.org/data/tf06/tf06_12-10f/tf06_12-10f.pdf

Spray Roundup on the Kentucky 31 (all of it) then re-seed with a blend of Kentucky Bluegrass in mid to late August.

Be prepare to water the following summer whenever mother nature does not provide, and also 3 to 4 fungicide applications to prevent fungal diseases from attacking/killing your Bluegrass lawn in the Summer. The heat alone in Charlotte will NOT kill Bluegrass.

I'm up in Raleigh, I have had a Bluegrass lawn for years now and I'm not the only one either.

BTW, most of the turf in NC is either Kentucky Bluegrass (western part of the state) or a combination of Bluegrass and Tall Fescue. There's a decent amount of Zoysia and Bermuda down on the coast, however.

Some Fescue grasses are just as dark green as Bluegrasses.

Click on the link below:

Here is a link that might be useful: NTEP test site in Raleigh for Kentucky Bluegrass

I would probably not use Midnight in a TTTF/KBG mix. Midnight is a great cultivar, but its very dark color and low growth habit might be too much of a contrast with TTTF. It is generally not a part of KBG/TTTF mixes available from seed sellers.

The ratio of seeds depends on a few factors. One is what percentage of each species you want to have in your lawn, the other is how many seeds of KBG there are per pound. TTTF is pretty consistent 225-235K seeds per pound, but KBG can vary from 900K-2M seeds per pound. Most of the popular cultivars have 1.2-1.5M seeds per pound. Most seed sellers sell a 90:10 or 80:20 mix by weight. 80:20 will give you roughly a 50:50 ratio of seed.

Thanks much Tiemco. Sounds like you know quite a bit about turf grasses.
Would I be ok with Midnight KBG and a Perennial Rye mix?
If not, do you have any suggestions on what would do well here in Charlotte(7b)? KBG that is.

I probably wouldn't recommend that for Charlotte. KBG/PR mixes do better out of the transition zone, and require frequent mowing to look their best as PR will outgrow KBG and have a somewhat shaggy look if you don't mow 2-3 a week. Also PR greens up much faster in the spring, which might look odd for a month or so before the KBG starts growing again. You might also have the PR go dormant in the summer, but that can happen to any grass in times of drought and high temps. Send me an email if you want if you want me to put you in touch with people in your area that grow cool season grasses.

You're fine overseeding with Midnight Bluegrass, you're not going to be able to tell the difference. Midnight Blue is not as dark green during the summer, it's more of a green to medium green at best. During the Fall when fertilized, it will turn dark green, but so is your Fescue.

Stay away from Perennial Ryegrass unless you want to grow it alone, which you can, but it will be much harder to keep it going this far south on most Summers. You actually have to fertilize Perennial Ryegrass during the Summer to keep it alive and looking good, something you don't do with Fescue or Bluegrass.

Either seed it alone or not at all.

Falcon IV and V are great cultivars in our area in regard to Fescue, Midnight, Award, Excurtion, Diva, Solar Eclipse, and Granite are a few Bluegrasses that do very well in Raleigh year after year.

If your grass is a lighter shade of green you need to amend the soil. Apply

Pelletized Lime, and a good hefty application of milorganite. Follow up with some

Scotts Turf Builder Starter and good deep watering for several days. Water early in the morning, and during hotter days water again mid day. Each time you water make sure you water enough so the soil becomes moist DEEPLY. Make sure your mower blade is very sharp and cut at the end of the day when the worst of the sun has passed. Set your mower blade high to leave some length to your lawn, don't cut it very short. Taller grass keeps the soil from drying out, and gives the grass more of a chance to be touched by the sun. The
green color is caused by the presence of a compound called
"chlorophyll," which the plant produces to do photosynthesis, which is
how plants get energy from sunlight.

I'm sure they figured it out at some point in the past 3 years.

What ever happened to tiemco?