Round-up isn't an overnight kill. Usually it takes two weeks before everything is brown and dead. Rototilling is probably not the best idea since it often leads to a bumpier lawn, and you will bring up some weed seeds. Let the Round-up do it's job (if you are mixing your own make sure you have the correct dilution). Once it's all dead and brown then scalp it with the mower, using the bag. Then I would probably core aerate and/or do a good power raking followed by a manual raking to remove all the dead stuff and to smooth is all out before seeding. Of course you want to do this right before seeding, not two months before.

If you rot-till you just stir up all those weed seeds and make conditions perfect for them to germinate.

Thanks! That was my fear about the rototilling. I'm killing the weeds now because I have some time on the weekend. I figure it will be easier and less stressful to kill them all now and just spot spray the ones that come up between now and when I plant on Labor Day than to try killing them all closer to the planting date. I'm also planning to core aerate a week or two before planting.

Tiemco - I hadn't thought about power-raking, is that to remove the last vestiges of the dead weeds?

Vertical mowing is to loosen the soil up to make it ready for planting.

The power rake will loosen up all the leftover dead stuff, it will break up the cores from the aerator, loosen up the top layer of soil, and fill in the holes to some extent with soil and the dead weeds (that's organic matter).

Seeding in Septemeber - a good idea

Fallowing (shallow watering along with normal rainfall) an even better idea.

Fallowing germinates any weed seeds lurking in the soil ... which you will kill along the way with additional RU.

jrodriguez90,

You may not want to hear this, but over the past 30 years in the business when you seed a lawn, you have to put up with weeds for the first season.

Hey thanks guys. Gary - I will try the fallowing. I'm hoping to get all the initial Round-Up work done by next weekend. Which should leave a solid month to try and coax the lurking shallow weed seeds out. And then to meet and greet them with some more Round-Up! lol. Is it wrong to enjoy spraying those suckers?

Texas - Yeah I know that there will certainly be some, I'm hoping that its a manageable amount though!