I don't know if there's a certain time that's not ok to do it. I usually do it anytime I notice the grass creeping over the driveway or sidewalks. Usually that means at the first mowing of spring, again every 3-4 weeks until the grass stops growing in the fall.

If by edging you mean using an edger to cut s narrow trench along the concrete I don't see why it should be tied to a time of year. In some ways it would be better in the spring so the material coming out of the trench could be worked into the yard. However it is more rewarding when you can see what you are accomplishing.

If by edging you mean trimming with a weed eater, I do it every time I mow.

Usually I can control the grass around the concrete with the weed eater, and only edge as above every couple of years.

I use my B&D electric edger at least once a month. When cutting the grass it partially fills up the edges so I use the blower for edging maintenance. Zoysia looks great with nice sharp edges ;)

Thanks for the replies. Sorry for the confusion. By edging I mean digging a small trench around my beds. I usually use a shovel stomp down and kick the dirt into the beds. I like the look of a deeper trench and sharp lines!!l Looks like I got some work to do this weekend. Thanks again.