Over seeding an established lawn is largely a waste of time, energy, and money, and does not need to be done IF you fix the problem with the soil that causes weak and spotty growth. That composted manure and sawdust can be a very large part of the solution since what your soil appears to be most lacking is organic matter. Use these simple soil tests as a starting place to take a good look at your soil.
1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer you soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.
and learn more about what it needs and contact your local office of the Virginia State University USDA Cooperative Extension Service about having a good, reliable soil test for soil pH and nutrient levels done. Once the soil is made into something your grass can grow into the grass will without the need to seed.

I have to agree with kimmsr that once you feed the soil, your grass will grow even without seeding.

We had a lawn which would go dry in early July and look like heck. After two years of tolerating it after we purchased out home, I began applying used coffee grounds (UCGs) which I collect daily from a convenience store. I would fling the grounds just before a rain making sure there were no big clumps. Everytime there was too many UCGs for the compost, it would be fed to the lawn which the worms love. We also never had worms and now there's lots!

A difference was seen in the first year and in the second year there were just minor spots. Now, after 5 years of doing this, DH is having a hard time mowing the lawn because it's so thick.

Your composted manure could possibly do the same thing. Do it before a rain and don't till.

Also, I'm not sure if you do this, but mow the lawn at a 2.5 to 3 inch height and leave the clippings on there. A thick lawn is more resistant to drought and the clippings will also feed the soil.

i'm having the same problem schmily.

so top dressing with organic matter will fix the organic matter in the soil, and bring worms and everything? even though theres no way they could penetrate the soil now?

West,

Yes is the answer to your question(s). Please keep in mind that this is not an overnight thing, but doing it this way and continuing to feed the soil with organics will give you longer lasting results.

Two of our neighbours decided to get their lawns off of 'steroids' and it was a rough start for them as they saw their lawns dwindle in the early part of the spring. One is beginning to show signs of good health and the other is growing quite well. Both are being top dressed with sifted compost just prior to rainy days. Next year should be nice for both of them.

Keep in mind that not all grasses will spread to fill in bare spots. Most tall and fine fescues will not spread except through tillers, which leads to a clumpy appearance over time. Some newer varieties of tall fescue are rhizomatous, although not as aggressive as KBG. Of the fine fescues, I think creeping red fescue is the only one that has rhizomes.

really the only thing i have been adding is alfalfa pellets every couple of months since last fall, i haven't really noticed a change, but like you said, i know it takes time and patience

and i don't think creeping red is very sun tolerant is it, bpg.?

People write in here about grasses invading their flower beds all the time, by stolens, tillers, rhizomes, or roots and what those grasses are looking for is nutrients. Give your grass the nutrients it needs, and the soil that will allow the roots to move around easily, and they will grow to fill in any bare spots you have. But that soil needs enough organic matter for that to happen and that can take some time. The organic matter that once was in the soil did not disappear overnight and will not get back into the soil overnight, that may take 3 to 5 years to get corrected if enough organic matter is added, but it will get there.
Any Fescue will grow in full sun, providing there is ample soil moisture, but they also tend to go dormant quicker if soil moisture levels drop.

I don't know about the sun tolerance of creeping red. It's often sold as being shade tolerant, but I've seen conflicting reports on how it does in sun. Some of what I've read has said that it does well in both.

Kimmsr--when you say the fescues will go dormant quicker, what do they go dormant quicker than? Certainly not KBG. I stopped watering my lawn a month ago (the only water it gets is what I give it). I've still got some green spots, but only where there's fescue or native grass. The KBG is long dormant if not dead.

The fescues in my yard go dormant quicker than does the Kentucky Blue Grass which goes dormant quicker than does the quack grass, but it may depend on which cultivar of blue grass you have because the breeders have come up with some pretty wimpy blue grass over the years.
I have noticed that some people here think that because their grass has turned brown dering the hot, dry summer weather that it died when in reality it has gone dormant, like grasses have evolved to do over the eons, and when sufficient soil moisture (and the air is cooler) is again present that "dead" grass will green up and grow again.

My next door neighbor's KBG goes dormant much faster than our tall fescue. I'll keep my fescue, I like it a lot better. Some of his bluegrass had invaded part of our yard years ago, before our lawn was established. That stuff gets brown at the first sign of dry weather. It (tall fescue) also spreads well to fill in small spots that die for whatever reason, but it can take several years depending on the size of the spot.

I occasionally have a spot die out for one reason or another. This spring when installing a new heat pump the guy moved a big garbage can onto the lawn and it sat there for 2 days, causing a big brown spot. I know it's too hot and dry to seed that now. In a couple of weeks, when cooler, hopefully wetter weather comes, I'll put a little compost there and grass seed, but only in that spot. We don't overseed the whole lawn because most of it is really nice now.

When we first bought this house the lawn was very sparce, more bare soil than grass. For several years we did core aeration in fall followed be overseeding and in a couple of years we had a full, thick lawn of fescue.

Karen

Thanks for all the replies. So my next question is how much should I put down at one time? There are spots that are completely bare red clay. I put a light coating down in the spring w/ the seed and now you can't even tell. I'm thinking several inches but not sure if this is one of those things that can be overdone?

I think you should be fine if you put down 1/4 inch to 1/2 inch of compost, even in areas where the grass is growing. If you have enough, you can put down that much over the entire lawn. The more you put down over time, the better your soil will be, although it can be a slow process.

Another thing to do is make sure you mulch mow your clippings. Bagging them takes water and nutrients out of the lawn.

Bagged clippings?!? Vat is dis? Perhaps I should have been a little more clear - this is a farm so we only have a lawn in the broadest sense of the word. We mow w/ a 60" cutting deck and occassionally let a couple of the horses graze through. :D