http://www.ppws.vt.edu/scott/weed_id/cypes.htm

I did the glyphosate thing on my front yard this late summer/early fall. loads of compost, fertilizer, seed, watered enough to float a large boat. now I have a mix of TTTF and FF in the shady area's. looks good.
thinking about it now, maybe I should have held off and worked on the soil to get the OM levels, etc. up first.
what does your recent soil test say?
next season I have a lot more compost and OM materials to spread. next fall I will overseed.
eh, maybe it doesn't matter where you start as much as just getting started.
good luck.

Was thinking of doing the soil test after all is dead and gone, so don't have one yet.

There is no glyphosate product made that is acceptable to an organic system. Aside from that glyphosate products will not kill nutsedges unless many repeat applications are made.
While many dispute this sedges, of which yellow nutsedge is one, grow mostly in soils that are too moist. Sedges are marsh, swamp, bog plants. Find out why your soil allows these to grow, correct that problem, and the sedges will not grow there.

I agree with kimmsr in this last post.

Another way to ask this question is this...
I'm going to nuke my current turf with RoundUp. What is the best way to recover and start an organic program after the nuking?

Where do you live?
What kind of grass do you have?
What kind of grass do you want?

I just noticed...you're the guy from Gilbert, AZ (South Phoenix) with a mix of bermuda and nut grass. I'm answering my own questions. I would wait to nuke the nut grass until you are a year into this. As kimmsr said, nut grass is a swamp grass and should die out on its own if you cut way back on watering frequency. It might be gone by spring.

hehehehehe, how do you get a wetland/swamp area south of Phoenix?
typical midwesterner here, always thought that was desert out there.
before you kill the sedge, look at this price list--
http://www.pawneebuttesseed.com/seedlist_wetlands.htm
sedge isn't cheap! hmmm, maybe work with what you have and turn it into a "naturalized area" (of course, No Mowing).

While sedges are wetland plants they will grow just fine anywhere they soil is moderately wet, such as where there is am automatic sprinkling system. Around here I see Yellow Nutsedge growing in lawns that have those inground sprinklers that come on every day and just moisten the surface soil, where Yellow Nutsedge roots, but not in lawns that are watered only once a week or so, soils that are allowed to dry at the surface but have moisture available for the grass roots deeper below where the Yellow Nutsedge roots.

"hehehehehe, how do you get a wetland/swamp area south of Phoenix? "

I live along the Wasatch Front, a desert area in Utah, and there's swamp land down the street from us. We don't get much precipitation, but the Great Salt Lake is only a mile away or so and the swamp down the street is in a low area. There are lakes and swamps in desert areas.

Didn't expect too many more responses to this. But decided to check back once I got back into town.

So decided just to wait and see what happens down the road. I have other things I want to do to the house, so the lawn will have to wait. I know I'll be coming back here and asking more questions though.

Thanks for all the responses.

You can create local areas of wetland anywhere by watering too frequently. Many people set their sprinklers to water for 10 minutes every day. A better way is to water for once per week for 1 hour - even in Phoenix. I learned that the hard way in an extended GardenWeb 'discussion' with a Phoenix based lawn professional. This watering method allows the surface of the soil to dry completely between waterings which prevents surface weed seed from germinating.

I used to drive through Phoenix neighborhoods a couple times a year before Interstate 10 came through. It was very typical to see their lawns sitting flooded. Apparently they would build the lawn 1 inch below the level of the surrounding concrete and use flooding to irrigate.