Does the Color Blue Repel Pest Insects? Or Spooks?

For the 100th show from my new home here in the Lehigh Valley I have chosen to resurrect the single most popular Q of the Week we have ever done. It's from 2015 and it generated more Internet action than...than...well, a lot of things, OK?!

It all started with a phone call from a listener who had been following our conversations about how to deter wasps and hornets from building their nests on or near houses--especially houses whose residents were allergic to {quote} "bee stings".

I say "quote" because I learned years ago that the culprits were generally yellowjackets or other aggressive wasps and hornets, and that most true bees don't sting.

That's right. Most of the hundreds of different species of native bees (like bumblebees, carpenter bees, mason bees, squash bees, sweat bees and ground nesting [or 'digger'] bees) don't sting people, even when that type of bee has a stinger...which is really good, as native bees are super-important pollinators of most flowers, virtually all fruits and a good number of your favorite garden veggies. (They don't call one very essential species 'squash bees' because they play a strange form of tennis. No bees; no zucchini! Or pumpkins, or gourds, or...)

The non-native honeybee, which originated in Africa and was domesticated in Europe, does sting, but you generally have to do something like step on one to get stung; and then that bee dies. Ah, but highly aggressive wasps and hornets (especially yellowjackets) will sting you just because they feel like it; and each one can sting you repeatedly; and generally, does.

Our caller said that his family down South always painted their porches a certain color that he called "haint blue" to keep stinging insects from nesting there. He said that he started doing it himself after years of having wasps build nests on his porch, and hasn't had a single nest since. I thought it was a pretty neat call; and then we were flooded with emails.

Bill in Gladwyne, PA wrote: "'Haint' means 'Haunt' in South Carolina, and the color 'Haint Blue' is used specifically around openings like windows and doors to prevent the entry of evil spirits into the house. I don't think it has anything to do with insects."

Deb in Philadelphia's Powelton Village neighborhood added: "'Haint' is a southern term for a ghost or anything that haunts, so I suspect that the traditional color "Haint Blue" might have something to do with repelling spirits."

Then we heard from George in Nether Providence, PA. (My first thought was: 'The Nether Provinces'! He's a spook! But it turns out that "Nether Providence" is a little area just outside of Philadelphia, near Swarthmore. Darn.)

Anyway, George wrote: "When we bought our home years ago, my mother insisted that we paint the porch ceiling light blue. She claimed it was an old "Pennsylvania Dutch" practice that would keep wasps from building their nests there. I painted the porch ceiling light blue, and no more wasps--paper or mud dauber--ever again. I have no idea why they stay away, but I can attest to the fact that it works."

So: what does this storied color really repel? Haunts or hornets? Spooks or stingers? Wasps or werewolves? Vampires or Vespula?

As Deb noted in her email, there are a huge number of web sites devoted to this mysterious color and practice (here's one current example: https://en.wikipedia.org/wiki/Haint_blue), but the one I found most authoritative was the Sherwin-Williams website.

Yes, that Sherwin Williams; the paint people. I quote from their web site: "Once just an old Southern tradition, the blue porch ceiling has made its way north and is being introduced to new generations. There are numerous theories as to why - from fooling spiders and wasps into thinking the ceiling is the sky, to blue being a harbinger of good luck, to the color extending daylight, to scaring away evil spirits...."

They continue, "Southerners, especially in the area of South Carolina, have a name for the ceiling paint used on porches - a soft blue-green referred to as Haint Blue. "Haints are restless spirits of the dead who, for whatever reason, have not moved on from the physical world," says Lori Sawaya, a Color Strategist they quote. She explains that haint blue, "which can be found on door and window frames as well as porch ceilings, is intended to protect the homeowner from being "taken" or influenced by evil haints."

Ah, but wasps get equal time. The page continues: "Some people swear that blue paint repels insects, leaving a porch bug-free and pleasant during those long summer evenings and afternoons...and this belief could be seated in historical truth...

"When blue paints were first used on ceilings, they were usually milk paints [that often contained lye, a known insect repellent.] As milk paint has a tendency to fade over time, people would repaint every few years, covering the existing coat with fresh paint--and fresh lye. But others theorize that insects prefer not to nest on blue ceilings because they are "fooled" into thinking the blue paint is actually the sky."

What do I think?

I think that if I had a porch, I'd paint it haint blue.