This spring I need to do a heavy overseeding because my grass is extemely thin, but if I don't apply preemergent at the same time I will have a yard full of crabgrass. I have read that I can accomplish this objective by using Tupersan, a preemergent that allows grass seed to germinate at the same time. However, Tupersan is not organic. Is there an organic alternative to Tupersan that will allow me to seed and put down a preemergent at the same time this spring?

You may want to post this under Lawn Care.