Staining protects deck boards from sun and moisture that would otherwise grey, crack, and rot the wood. Timing and prep determine whether the stain soaks in and lasts or peels in a season.
Clean and let it dry
Clean the deck with a deck cleaner to remove dirt, mildew, and old flaking finish, then let it dry thoroughly — usually a couple of dry days. Staining damp wood traps moisture and causes peeling.
Choose your stain
Transparent and semi-transparent stains show the wood grain but need more frequent reapplication; solid stains last longer and hide imperfections but look more like paint. New pressure-treated lumber often needs to weather before it will accept stain.
Apply thin and even
Stain in dry, mild weather out of direct hot sun. Apply thin, even coats with a brush, roller, or pad, working a few boards at a time and back-brushing to avoid lap marks. Don't over-apply — wood can only absorb so much.