Yes, a garden sprayer makes a suitable tool for staining your fence. You get a consistent covering of the surface that's similar to a spray gun. Since fence stains usually have a thin consistency, they are easy to apply with the sprayer without clogging the system. Spraying is much more convenient than hand-painting on the stain. However, you'll need to ensure you clean the sprayer properly after use before the stain dries inside the wand, line, and tank.