What does the label say?

BTW, you might be interested in reading this about nutsedge:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7432.html

Here is a link that might be useful: nutsedge in home gardens

what did you spray? if it a chemical that kills the plant when the plant itself is sprayed like roundup you should be able to replant immediately. if you used a soil treatment read the label. i've been spraying spectracide on the nutsedge after covering the plants i want with overturned plastic pots to protect them. after the 5th spraying the sedge is finally disappearing. i read on a state agriculture web site that after repeated spraying & pulling the 'nuts' eventually lose their potency & become too weak to regenerate new growth. i gave up on my vegetable garden this year & have sprayed & tilled it weekly. i'm finally seeing the light at the end of the tunnel.

Image, "imazaquin", is a product of lower toxicity than Spectracide.
Control of nutsedge requires some understanding of the plant and its origins. All sedges evolved in wet lands and the Yellow Nutsedges, Purple Nutsedges, and others grow best in soils that replicate wet lands, moist.
There will be those that will state here that the people at the University of California, or any other state university, do not know what they (those with pHDs) are talking about.

Here is a link that might be useful: About Nutsedge

I know that the primary nutsedge I have is yellow and I know that it came in with topsoil when we built our raised flower beds several years ago. I have dug them up, pulled them up and as a last resort sprayed with Image. I also understand that nutsedge grows best in moist conditions which we definitely have. The label is not specific about replanting mature plants - only about reseeding with grass.
Thanks for the links about nutsedge but I still am wondering about the effect of replanting in the same area where I recently sprayed.

you probably should wait a couple weeks. The label suggests you spray it in w/in 1-7 days.

Call them to be sure. 1-800-265-0761