30 seconds Spray & Walk Away is specifically formulated to kill lichen, moss, mold, and algae. Ideal on roofs, pathways, sealed brickwork, asphalt, driveways, siding, wood decks, and other hard exterior surfaces. Safe for use around plants, gardens, and where children and animals play, when used as directed. One easy step, spray and walk away. No rinsing, scrubbing, hosing, or pressure washing needed. Mother Nature does all the work, eroding the treated matter while it decays over several weeks. Biodegradable. Bleach and phosphate free.