Scotts MossEx 3-in-1 Ready-Spray is a fast-acting formula that effectively controls mosses, algae, lichens, and liverworts. The product gets to work within hours, and does not stain concrete or other surfaces. Apply on lawns, ornamental gardens, around homes and on roofs, patios, decks, sidewalks, and more (as listed). It can be used at any time during the year; however, best results are obtained with actively growing moss in the spring or fall. To apply, simply connect the sprayer to a garden hose, turn on the water, and spray, keeping it moving for an even application. Applying this product in calm weather or when rain is not predicted for the next 24 hours will help to ensure that wind or rain does not blow or wash pesticide off the treatment area.