Grasses will, when temperatures go high and there is a lack of sufficent water, do dormant. They do not "die" although many people think so. Most of our turf grasses evolved doing just that, when heat and moisture was not to the grasses liking they went to sleep until conditions improved.
"Weeds" have adapted to grow even if soil moisture levels are pretty low so they will contimue growing even when your lawn is dormant. If you are not going to provide sufficient moisture to keep the lawn growing, a minimum of 1 inch of water per week, there is little you can do.

Look around the neighborhoods in town. They will be either bermuda or St Augustine. Both can be very nice but bermuda requires a change in most people's life style to maintain to a nice level. It requires mowing twice a week at a low setting and a monthly app of a high nitrogen fertilizer. If you can't provide that, it will look brown, straggly and weedy.

St Augustine can be maintained with much less hassle. Mulch mow it at the mower's highest setting, water it weekly in the summer heat and monthly in the cool months. Fertilize with organics any time you want. If you fertilize monthly it will look incredible. If you do it less often it can still look very nice.

Thanks for all your suggestions.

The lawn really appears dead in the "dead zone." All my neighbors' bermuda is green and living (though they do use fertilizer etc). But I haven't seen any of them watering their lawns. I watered mine lately and it rained too and there wasn't a change in the lawn.

I've examined my dead zones and it looks like there isn't really anything there. I'm actually thinking of digging those areas up a bit later this summer when it's a little warmer and seeding with some more Bermuda. I just think I need to put down some corn meal or whatever it was someone was suggesting as food for the grass. My soil LOOKS bad to me. I haven't done any soil tests or anything, but it looks compacted and dead. I have chickens in my backyard. I may just take some of the chicken poo after it has sat for several months and apply it to the front yard. And maybe some compost too, once it's sat awhile. I also have grass clippings in the back. Maybe I need to spread them out on the front lawn too.

Any suggestions? Or would I be making mistakes doing these things?

P.S. I don't know if it would be quite warm enough for the St. Augustine grass. Plus, I'm looking for a cheaper solution than redoing the entire lawn.

Once grasses go dormant it can take a very large amount of water to get that grass to start growing again. Some rain and a bit of watering is not going to do that, it will take a lot of water. The time I spent working on gardens around Nashville taught me that Tennessee soils, like most others, lacked sufficient organic matter and they would become compacted and plants would have a difficult time growing until adequate amounts of organic matter were added to the clay.
What happens to the leaves from those deciduous trees the grow around you?

The leaves we were keeping from all our deciduous trees we just recently put all around our flower gardens in the front to keep down the weeds-like a mulch. Would they be better than grass clippings or CGM to get the levels of organic matter up? I still have some amount of leaves (not like I did before, but...)

Should I poke holes to aerate?

How much watering should be going on? Twice a week for an hour at a time? More? Less?

Thanks!

While bermuda can be beautiful, it is a hassle to keep it looking nice. It is one of the few grasses that should be mowed at the mower's lowest setting. Partially due to that, it should be mowed twice a week during the summer to keep from scalping it every week. Bermuda also needs as much water as all the other lawns if you want it to be green. The idea that it needs less water depends on your tolerance for brown grass. When bermuda gets very dry it becomes dormant and turns brown. When St Augustine dries out completely, it dies. Thus you have to water St Aug to keep it alive but you could stop watering bermuda altogether and it would remain alive but brown. Bermuda also needs monthly doses of high nitrogen fertilizer to stay green.

This is to say that you can have a bermuda lawn but if you are not willing to maintain it, it is going to look raggedy. It can also thin out and become a haven for weeds.

Back in the 50s, before the modern herbicides became inexpensive, when you bought grass seed you got a mixture of a fescue, Kentucky bluegrass, rye, and even clover. The idea was that one of the grasses would dominate in almost any soil and you could have a green lawn with multiple species of plants. That approach is one you might consider. You are in the transition zone meaning that you would be able to grow almost any grass.

Thanks for the info dchall_san_antonio! Can you recommend where one might be able to get the kind of grass seed combo you are talking about?

Personally, I'd like a low maintenance lawn (as you might imagine from our years of neglect). We hate wasting water on grass. And we mow it probably every two weeks or even three. The weeds get tall. Yikes! And yes, the bermuda is thinning out and raggedy and I think that's why the weeds have dominated.

I guess I'd be willing to water more if I absolutely have to. My brown lawn does look pretty bad.

Fertilizer-I read a book about what they put in fertilizer- Fateful Harvest by Duff Wilson- hazardous waste leftovers and now I'm not interested in commercial fertilizers at all.

The lawn has all but been ignored.

The people at your county office of the University of Tennessee Cooperative Extension Service will be able to help you identify the grass you have.

Here is a link that might be useful: UT CES

Given the new information, you might be happier with an unconventional grass. Western wheatgrass is more at home in the midwest but you are in western TN, so it might work for you. WW is grown as a crop grass for cattle but when it is mowed down, it forms a dense ground cover. Here is a picture of bpgreen's lawn in Utah.

{{gwi:83633}}

His is a mix of wheatgrasses, blue grama, and strawberry clover. In Utah you can do that because most of the wheatgrasses thrive there. In TN it looks like the Western variety is the only one that might work.

Why use western wheatgrass? Because it needs very little water and almost no fertilizer. bpgreen mows about once a month. Sounds like it might be a good match for your lifestyle.