Why Are Missouri & Illinois Barns Painted Red? – It’s Science
I always thought that the reason my grandma's barn and others were painted red was because of tradition. That's partially true, but I've learned that there really is some science behind farm structures being painted bright crimson.
The history of both sides of my family are firmly rooted in farms. I suppose that's why I got curious about why most of the barns on the properties were red. The answer is more complicated than you might know.
Is it because red makes barns stand out from the green pastures so cows can see them better? Nope, although that is an extremely funny thought.
This Old House said that one simple answer is that white paint a couple hundred years ago was much more expensive than red. It was more than a money issue for the paint though. Amish Country added that "ferrous oxide, or rust" was added to the paint used "because it killed fungi and mosses that might grow on barns, and it was very effective as a sealant. It turned the mixture red in color". Like I said, science. The rust would also ironically preserve the wood from decay. Go figure.
Now as to the question of why barns are still painted red a majority of the time even though paint is plentiful in any color and there are chemicals that can treat wood for longevity...this is where tradition comes in. You'll still see new barns constructed painted red as a tip of the farmer's hat to those who worked the land before them. Science and tradition happily married together.