When we built the house last summer, the pine was fresh and very light in colour. Sooz wanted to keep the inside floorboards that fresh and light so we had them sanded and treated with white oil.
We put clear stain on the deck to help keep it light, although I wish I had done the first coat last October instead of this May.
We had planned all along to let the house itself weather for the first winter, and then to protect it with "Jarn Vitrol", which is a very Swedish product. It's essentially an iron powder which, when added to water, and sprayed or painted onto wood, accelerates the weathering of softwoods to a silver-grey. It's also possible to add a coloring agent to help adjust the tint of the solution to make the color more uniform. We chose a standard silver-grey tint to add to ours.
Rutger and I used a garden sprayer to put the jarn vitriol solution on the house and it went pretty well, with one big exception. Because it is water based, it's very thin, and it's also pretty much invisible when it first goes on; the greying of the wood doesn't become apparent for a few hours. So, when I removed the masking and tarps from the deck, the doors, and the window frames, I found a number of grey spots and streaks in places I didn't want them.
Both doors, especially the little house's, have grey drips on the fresh wood. We had hoped to keep the doors light and natural, but the darkening can't be removed, so we're going to have to paint over the doors now. We will probably do the window frames, too, as there are stray spots and drips on the otherwise light pine. I'm very annoyed.
The deck has a few spots on it as well, but it was going pretty grey in most areas already, so most of those marks aren't as apparent. I'm thinking about having the deck sanded or planed at some point in the future, so that's less of a problem. It's the doors which are a disappointment.
Sooz looked into stain options and found a nice darkish blue which might go well with the new grey colour of the house. Doors are traditionally blue on summer houses, anyways, so this might end up being a more appropriate result than the light pine in any case.
Lesson learned for the future, though: jarn vitriol is insidious. Handle with care.