It is very difficult to transition from one grass type to another without first killing the existing lawn. Strike that, make that nearly impossible.

I've read estimates that as little as 10 percent of your new seed actually will get established by basic overseeding. At that rate, it might take 10 years to completely transition. And during that time your lawn is sure to look a mess (especially trying to convert to Bent)

If you are sure you want a Bent grass lawn, kill the existing lawn first. You'll be glad later on that you did.

Likw I said in your last posting. If you're going to do it, do it right. Bent does not play nice but it isn't going to totally choke out the existing grass either. Instead both grasses will not be optimal. Do what turf toes said. sacrifice one of them.

Execute it! You could use horticultural vinegar if you'd rather not use Roundup, but definitely get rid of the lawn.

I didn't want to fight with two different types of bluegrass, much less different species like you have.

overseeding existing grass with bent is the way to go. i like the look of a mix of different grasses. If the grass is consistently kept cut at bent grass height, the bent will eventually(gradually over a few seasons) take over. killing the whole lawn is never an option in my eyes.
of course my 'methods' are far from the 'reccomended' ones...but they work. :)

quirky... some advice:

The bentgrass has been up for about two weeks now. Yesterday I put down some fertilizer with nitrogen and phosphorous as the main components...

When can I cut back my watering frequency? Days have been averaging 80-85 and nights 55-65. Ground is staying wet all day now (I'm watering at 10 am and 4 pm for 15 minutes). I don't want to water too much, but yet don't want it to dry out and die.

Any ideas quirky... or anyone?

Here's what I did to answer that question for myself. I took my turf hound aerator and jabbed one end of it in the ground as far as it would go. Then I pulled it out and popped the core out with a pencil. I then held it there in my hand and measured how deep the roots extend from the soil surface.
Oh dear! The roots only go down 3"! How am I going to keep this stuff alive?!
Bottom line, is bent is not deep rooted. You need to keep that in mind and perhaps water more diligently than you would with traditional grass. You don't need to ground to be soaked all the time.

During the cool season I watered once a week if there was no rain. It seems to be tolerating one to two waterings a week now with rain.

Updated pictures of the front yard. It was overseeded with bentgrass early July with a heavy dethatch and addition of topsoil. It was just mowed at 1".

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And here are some pictures of my trial bentgrass bed that I planted last July. So its now a year old. I planted a flower bed by my house to see how bentgrass would look mowed at 1". This is what gave me inspiration to convert my lawn to bentgrass.

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It's funny.... "I just planted this in early July"
OK , it's still July and it looks like that lawn has been there for eons. Good work. Of course I know htere's some tall fescue or whatever that is existing but I didn't notice it in the pics.

Yeah, there's some other grass in there like you said. I didn't want to chemicalize the whole lawn with roundup. I'll let bentgrass win the war on its own. The tall fescue won't like being mowed at 1" so the bent will eventually win.

And, yeah I did plant it early July. The top half by the house was done July 2, and the bottom half by the sidewalk was done July 6. At the top of this thread I posted pics taken on July 14. You can see a lot of bare dirt in those pics. Its filled in nicely, especially for a July planting. Whoever says you can't plant a cool season grass in summer has to be wrong ;).

In two weeks I'm having 10 yards of topsoil delivered and I'm doing the same to the backyard. Cut at 1", vigorous dethatch with a power dethatcher, put down 1/2" to 1" of topsoil and seed at 2-3 lbs per 1000 sq ft.

Now I have to convince my dear condo neighbor (I live in a side x side condo) to do his front yard the same.

Well, seeds are ordered for the backyard. Penncross creeping bentgrass from outsidepride.com. I have 10 yards of topsoil coming Friday which will cover my backyard at 1.25" per my estimation. I will power dethatch multiple times which will rip out the existing grass to root level, cover everything with the topsoil, spread the seed and see what happens. I plan on spreading the soil and seed on Saturday August 4th. Should I cover the seed with straw, or just leave it bare dirt?

I plan on posting pictures of the progress.

You can plant a cool season grass in July. No law against that. Getting it to survive August is another matter.