Q.Is my ground contaminated or safe?
I sprayed Crossbow all over my garden area about 2-3 weeks ago. I now have NO worms. Is the poison broken down enough to plant there? Safe? Edible?

On the label of the Crossbow Herbicide it will tell you how long after application you can safely begin planting. In using any pesticide, the most important thing is to read the label carefully. This article will tell you more about herbicides: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-long-does-weed-killer-last-in-the-soil.htm
I could not find anything in the literature about Crossbow's effect on worms.