When a deck is brand new usually the lumber is still very “green” and has a high moisture content. That is unless the lumber is KDAT lumber meaning, “kiln dried after treatment.” This type of wood is dried before it is sold. But for the average deck being built, regular cedar, redwood, or pine is used in the construction. You may have heard the term “season” and how it is important to let a new deck season prior to staining it.
To season a deck simply means to let it sit, for a season, before you attempt to stain it. This is because the wood still has too much moisture in it and staining it can trap that unwanted moisture. This can lead to many moisture problems like mold, fungi, rot, and decay. This term can be a bit misleading though. Normally a deck does not have to “season” a whole year. Many times, depending on weather and sun exposure, a deck can season much quicker. In most cases a new deck can be stained within 3-12 months of being built especially if the weather has been warm and the deck gets a lot of sun exposure.