Can you link the previous suggestion from Morpheus?

http://forums2.gardenweb.com/discussions/3008954/logan-labs-results-advice

The only thing I might do differently is slit seed instead of dethatching but that can depend on how thick your lawn is that you've killed off.

As for the RU, the active chemical breaks down rather quickly so over spraying shouldn't hurt anything. I don't know if there is an annual usage limit, I doubt it so you should be fine. Just make sure you have not used the 365 formulation.

Given your overseeding, let's shift that plan a bit. I don't want to push it further than October 15 even in NC, but I don't have to. Four pounds isn't all that much, and we'll probably have to continue liming a bit after your next test next spring. Your sandier soil is the limiting factor there.

Assuming decent (warm) weather, your grasses should be showing distinct stress from the RU already. If not, reapplication is probably necessary. As Julian noted, it breaks down fast, doesn't have any impact on seeds, and won't cause problems in your new lawn. I actually area sprayed RU the day I seeded, but did try to limit the amount and area I sprayed with the stuff. It all went off without a hitch.

Revised Plan:

September 1: Apply starter fertilizer at bag rate.

October 1: Apply starter fertilizer at bag rate.

October 15: Apply Mag-I-Cal or Encap at 4 pounds per thousand square feet.

November 1: Apply starter fertilizer at bag rate.

Hmm. Slit seed? You're the first person thats recommended that to me. Most I've seen caution against it due to stirring up weeds. Is it really a necessary? My lawn is patchy and very sparse. Not really thick at all.

Morpheuspa,

I'm intending on seeding around Sept. 8. That starter on Sept. 1st combined with another full bag rate on Oct. 1 won't be too much for the new seeding?

You can slit seed if you want, and if the existing dead grasses are very thick. It'll help with seed-soil contact, although it isn't strictly necessary if you don't wish to. Slit seeders should be set to barely (1/4" or a little less) nick the soil, and won't cause excessive problems with additional weeds. They also disturb the soil too little to cause problems with the biology or structure.

The starter is actually going to be an advantage for the new lawn. The September 1 app won't bring much nitrogen to the table as the new roots won't be able to absorb it--but it does add phosphorus, which hangs around indefinitely and waits.

By October, the new grass will want a gentle feeding, and starter is on the low end of nitrogen feeding.

Doing things perfectly? In addition to the starter, I'd drop Milorganite, soybean meal, or cottonseed meal with the seed (it won't release until 3 weeks later and gives a gentle feed for some months), and then do it again on October 15. That'll give your new lawn a good base of slow and fast nitrogen to grow on.

What did I do? I poured on organics during seeding and the first fall at fantastically high rates, but already had a soil that had adjusted to organic feeding and could handle it easily. Development of the new lawn was incredibly fast and strong.

Awesome. Thank you.

So just to re-iterate, I can still achieve satisfactory results by broadcasting and rolling?

Broadcasting and rolling will be just fine. I'd strongly advise cutting your grass as short as possible and bagging it once it's dead to remove as much mass from the area as possible, though.

Confession time: I seeded into a thick base of dead lawn and didn't even bother rolling. I can't handle a half-filled roller at my size and weight (at the time, 120 pounds).

I did irrigate more heavily the first time to get the seed to settle, and I'd also covered it in about 1/8" of peat moss to mulch it. Problems, none.

Slit seeding is just another option and as Morpheus added you will get better seed to soil contact which is necessary for germination. I would stick to what Morpheus suggested though as he knows your situation better.

Yeah I had planned on scalping as short as my mower would go.

When you say you seeded into the trick grass, did you broadcast or slit?

I broadcast.

Again, it was a matter of comparing my mass (small) to the machine's mass (not inconsiderable) and realizing that I couldn't push the stupid thing across 10,000 square feet.

Is slit seeding better in thick dead stuff? Yep. Necessary? Nope.

Great.

Lastly, if I can ask, how much of a Glyphosate mix do you guys use? The generic 41% I bought said 2.5oz/gallon which covers 300sqft. I used a 4 gallon backpack sprayer to do my 15,000sqft. By the math, I should have used a full gallon of the glyphosate. But I didn't, I probably only used about 2/3 of the gallon. I was worried I didn't use enough so I asked a landscaping guy and he said I still used too much lol... Just curious what has worked for others.

A two-thirds rate, well distributed on the grass, should kill it just fine.

I used a hose-end, and accidentally overapplied a bit. My grass looked incredibly shocked by day 3.

I kinda like it when people come here before they start a project, so the plan doesn't get hitched up from the git-go. If we could step back in time to the day you sprayed the RU, what you could have done was to begin short duration watering on a daily basis to germinate all the remaining weed seeds in the lawn. Then a week later you could spot spray those green spots with RU to kill the weeds. Then you could go on to the slit seeding or dethatching with much more confidence that you wouldn't have a weed problem.

The Lord took care of that for me. It rained quite a bit the week prior to me spraying. Believe me, my lawn was thriving.

Really my concern is that I didn't hit the lawn hard enough with the RU. I'm day 6 now and the crabgrass is yellowing out and the fescue/blue/rye are getting stressed but they still have a little color. I would have thought everything would be brown by this point.