For best results, apply Lilly Miller's Moss Out. For roofs and structures just prior to the time when fall rains begin or in early spring. Moss growth can occur in nearly any location where dampness persists. Such areas include roofs, decks, steps, patios, walks, fence posts and foundations. Since moisture is essential, most moss growth appears during the fall, some in the winter and in the spring. Very little moss forms in summertime. Destroying existing moss is done most effectively during times when its growth is most rapid and when rain is not expected for several days. Controlling moss may add months or years, of service to roofs, patios and such areas.