If your front lawn is 90% Bermuda there really is no reason to seed it. How often do you fertilize?

I try to fertilize once a month, but in practice it might be every two months :P 90% is my guesstimate, it's hard to say exactly but I think it's still closer to 90 than 80.

There are one or two bare spots that were considerably larger than the others because of so much dallisgrass clumped together, I worry they'll fill up with weeds before the grass grows in. I know I need to mow it more though.

Bonus S isn't labeled for use on bermuda.

You are right of course, and I knew that. I misspoke, I use Turf Builder with Plus 2 in the Spring, the yellow bag ;)

From my experience, pulling nut grass won't get rid of it.

I agree that you shouldnt need to seed. If you properly feed and water the existing bermuda it will fill in the dead spots, likely before first frost. If you still want to plant seed, I'd suggest raking the topsoil to loosen it up, laying the seed, rolling it in with a lawn roller to ensure good seed to soil contact and keeping the soil moist until seedlings are atleast an inch tall.

Now core aerating will do alot for reducing soil compaction and allowing more water and oxygen to reach the rootzone, but it will also bring about a million weed seeds to the surface. So unless you plan to rake up and dispose of the cores, be prepared for many more weekends of weed pulling. Your other option, and better in my opinion, is to strat a soil conditioner regiman like aerify plus, which will also loosen up the soil and at the same time increase organic matter in the soil.

Going by the experiences of others here over the years, you will have a lot of trouble getting rid of coastal bermuda. In Florida they call it torpedo grass (do a search). As far as I know nothing will look good with coastal mixed in, and you aren't getting rid of it.

Nutsedge is a swamp grass. If you are watering too much or if you have underground water bowls, you can stop nutsedge by stopping all the water. There is another sedge called kyllinga that looks like nutsedge but thrives with no water. It is far less aggressive than nutsedge but still persistent and unsightly. Sedgehammer is the name of the product that seems to treat either of those.

With your lifestyle I would try to adjust to keeping the weeds at bay and letting the coastal take over.

How often are you watering and for how long?

I doubt my sandy soil is actually compacted, so the aeration is possibly not really needed.

I'm resigned to living with the coastal. It's not so bad, I just need to keep the weeds under control so it doesn't devolve into something worse. I like to mulch mow, but if I let it go too long it's hard to do. The front was pretty thin and weedy when I moved here, with a big expanse of white clover being it's best feature. Since I've been fertilizing and killing weeds the coastal has sprouted on the front lawn with a vengeance, save for the current dallisgrass battle scars.

I am not watering with any regularity yet, as we have had sufficient rain for the bermuda to thrive. I could start doing an inch a week easily enough I guess.

The nutsedge is very sparse. I might get some packets of sedgehammer and keep handy. Maybe it will get worse.

Actually another idea occurred to me today -- I have a relatively unlimited supply of thick bermuda in the back. Why don't I just cut and transplant my own grass plugs? Anybody ever do this? Will it work, and how deep would I need to dig, 3-4"?

One reason is there is a 2' strip between the sidewalk and the front curb that was about 95% dallisgrass infestation, and I killed it all, except a lonely couple feet of bermuda right in the middle (and my lot is 100' wide). It's going to take that dab of bermuda eternity to fill in, but the plugs might really get it jumpstarted and could be planted in the larger bare spots in the yard too.

Plugs will absolutely work. Bigger the better.

Have you thought about mixing the white clover with bermuda and letting it run rampant? Clover is only a weed if you really don't want it. A friend of mine opted to let the clover come in on his bentgrass golf course up in Canada. Apparently all his problems were resolved with the mixed varieties and with a change in his mowing.

I don't care for clover to be honest, but the Plus 2 pretty much exterminated it when I put it down the first time last year.

I can see the bermuda really is going to fill in for the most part, but I think I will try to help it along in the larger bare spots and along the curb with some plugs cut from deep in the back 40. With the dallisgrass licked it might actually turn into a nice lawn. Going to fertilize again this week!