Nope. Like many of the larger weeds (bloodweed, poke salat, lamb's quarters, and the infamous ragweed) they like freshly turned earth. All it takes is a windy day or a bird pooping and you've got a field full of 'em.

They're an official PITA in the garden.. especially larger gardens, cause they'll take over and crowd out the stuff you want growing. At least most of the stuff is edible!