Fun idea, but I can see a potential problem when the time comes to mow. I think the glowing rocks need to be contained somehow. Or maybe use larger painted rocks to line a walkway and just plan to use an edger for trimming the grass.
DIY Weed Spray. Makes 3 gallons for around $4.00. Works better than Round Up! Killed the weeds/stray grass on first application. One gallon of APPLE CIDER VINEGAR, 1/2 c table salt, 1 tsp Dawn. Mix and pour into a smaller spray bottle. (you can purchase 3 gallon size Apple Cider Vinegar in the canning section of a good hardware store - cheap!)