There are some little things that look like moss growing next to the Dill. They don't really look like tiny Dills, but I have no idea what it is.
The pot is on a 5th story window in a very urban part of NYC so it's unlikely to be some spore or something that flew in the window; also, all the other pots next to it don't have this moss growing in it. The soil all came from the same bag too.
Sorry, the pictures aren't great.