I need to do a complete lawn makeover. I was thinking about embarking on this next season. At this point I have 50-100% weeds and I think only a completely new lawn will suffice.. I was figuring on killing off all the vegetation next year and then reseeding. I will probably use several applications of an organic weed killer such as concentrated vinegar or Scythe, since it is too large an area for smothering. (I estimate 15,000 sq. ft.)

Is there any way to establish a new lawn without rototilling? I understand the problems that tilling can cause, in terms of creating lumps and bumps. However, I already have lots of lumps and bumps and I clearly need some grading as well, to smooth out a raised bed that was formerly a perennial garden, and to deal with a small swale in the backyard. I am also planning on adding copious amounts of compost and/or topsoil, since I mostly have crummy sand left behind by builders.

One additional question--is there any point in adding compost this fall? The soil is terrible and I would like to start improving it, but as I said, at this point I would be mostly helping out the weeds.