Why are barns red?

Barns began being painted red in the late 1700s by farmers using a recipe of skimmed milk, lime and red iron oxide, a protective paint that was inexpensive to make and lasted for years. The red paint gained popularity, starting a tradition that continues as of 2014.

Early New England farmers didn't have extra money to spend for paint, so many barns were unpainted. The iron oxide used in the mixture was easy and inexpensive for farmers to obtain from soil, allowing many more barns to be painted. Farmers realized the paint absorbed heat better than unpainted barns, helping to keep their barns warmer in winter, further spreading the popularity.