Vermont Natural Coatings PolyWhey Exterior Penetrating Stain is a water-based stain and water proofer in one, for decks, fences, docks, raised beds, outdoor furniture and siding. It comes in 14 colors, in 8 oz samples, quarts, gallons and 5-gallon pails.

It carries color and water proofer deep into the wood and protects it from moisture and UV: the look of a stain with the protection of a sealer. Use it on new, pressure-treated or weathered wood. It isn't recommended on IPE, mahogany or other exotic woods, and it doesn't go over a finish; if the wood has an oil-based or water-based stain on it, sand off the film so this can soak in. A gallon covers 200 to 400 sq ft, depending on how porous the wood is, and it cleans up with soap and water. The colors are Caspian Clear, Autumn Red (quarts only), Lakeside Cedar, Acorn Brown, Sterling Gray, Charcoal Gray, Coastal Gray, Granite Gray, Bison Brown, Brackish Brown, Royal Cherry, Golden Cedar, Balsam Green and Garden Green.

Stir well and test it on a sample piece first. Apply with a brush, paint pad, foam brush or spray, evenly with the grain, keeping a wet edge, and coat the end grain of every exposed board. Don't thin it. Two coats are recommended, and the second must go on while the first is still damp: once the first coat dries, the second can't soak in. Don't sand between coats. Apply at 50 to 80°F air and surface temperature and 40 to 60% relative humidity, when no rain is expected for 48 hours. Under normal conditions it's fully cured in 48 hours.

Don't let it freeze. It's water-based, so in winter it can freeze on the way to you. Keep that in mind when you order in cold weather, and store it somewhere warm once it arrives.

Andrew Meyer founded Vermont Natural Coatings in 2004 in his hometown of Hardwick, Vermont. Its patented PolyWhey formula uses whey protein, a byproduct of cheesemaking, as a co-binder in place of some of the harsh chemicals in typical wood finishes.