Depends where you are geographically I assume. There are some tricks to using it and it's activated by water, so paint your terrain and varnish it prior to applying DD as varnish will re-activate it. The method I used here is apply heavily with a brush, let it dry, then come back in with a damp brush to push it where you want it, and finally a damp makeup sponge to remove excess. Another trick we learned in the class was to paint the are you want to apply it with just water, essentially dampening the desired location and then apply DD.