If you’ve spent any time driving through any of the farm countries in America, then you’ve probably noticed two constants. Red barns and white farmhouses. We can’t really tell you why so many of the barns out in the country are painted red, but we can give you the three specific reasons why almost every farmhouse you see is painted white.
First of all, the white “paint” on farmhouses isn’t actually paint in most cases, and back in the old days, it rarely was. It’s “whitewash.” Whitewash is a simple mixture of lime, water, and salt. The ingredients are relatively inexpensive and whitewash can be made at home. It’s much less expensive than paint.
Secondly, the lime in the whitewash protects the home’s outer materials, especially wood, from mold and mildew. That’s just one reason it’s common to see farmhouses that are a hundred years old or older that are still in great condition.
Thirdly, white wash is perfectly healthy for animals as it contains no toxins. If you’ve ever had goats, you know they like to eat just about anything. Whereas paint chips could harm them, if they eat white wash covered materials, it will generally do them no harm.
source- Wide Open Country