Why Is a Four-leaf Clover Lucky?

As is often the case, it all goes back to Eve. Legend has it that as she and Adam were being hustled out of the Garden of Eden, she plucked a four-leaf clover to carry with her as a souvenir of Paradise [source: Elmerhebe].

The druids of the ancient Celtic world wouldn't have known Eve from Adam, as it were, but they too were big fans of four-leaf clovers and carried them around to ward off evil spirits [source: Ventura]. This practice evolved into a medieval theory that a four-leaf clover would give you the ability to spot fairies and take evasive action if necessary.

As a result, back in the Middle Ages, kids entertained themselves by ferreting out the necessary stems and heading out for a fairy-hunt. Obviously, that's a video game just waiting to happen [source: Evans-Wentz].

With the little green clover plants enjoying such popularity, it's no wonder St. Patrick decided to use them as a teaching tool when he set about converting Ireland to Christianity.

The four-leaf variety being in short supply, he settled on the ubiquitous three-leaf clover to explain the three-in-one nature of the Holy Trinity to the heathens. One leaf stood for the Father, one for the Son and the third for the Holy Spirit, all united on the single stem of the Godhead. Centuries later, the clover has become closely associated with the holiday of St. Patrick's Day.

Similarly, a poem in the popular tradition holds that the four leaves on the lucky clover signify fame, wealth, health and faithful love. Along these lines, the English have a tradition that if you dream of clover, you're guaranteed a happy and prosperous marriage [source: Faust].

West of England, in Cornwall, some people alleged that if pixies stole your child and left a changeling in its place, the only way to get your own offspring back was to lay a four-leaf clover on the impostor [source: Evans-Wentz].

You know that saying about not seeing the forest for the trees? The same rule applies here. The experts say don't waste your time pawing through clumps of clover. Your best bet is to visually stake out an area the size of a typical office desk (about a square meter or yard) and quickly scan it.

If anything out of the ordinary snags your attention, look at that spot more closely to see what it was. If not, move on to your next square and scan again. Remember, your chances are one in 10,000, so you've got to be efficient about this [source: Olsen].

Clover is a type of pea and is valued by farmers for a few reasons: Cows like to fill their faces with it; bees like to fill up on its nectar and the plant itself likes to fill its boots with nitrogen.

That's to say, clover is very good at pulling nitrogen from the air and rooting it in the ground for other plants to eat. There are 300 species of clover, but the best one for soil is known as white clover, or Trifolium repens [source: Faust].

Trifolium repens also happens to be the kind of clover plant that produces the lucky four-leaf aberration. That fourth leaf, it turns out, is the result of a suppressed gene that fails to be suppressed. Nobody's exactly sure what causes this to happen; but, for whatever reason, it rarely does. Very rarely [source: Olsen].

As mentioned earlier, your chances of finding a four-leaf clover are a measly one in 10,000. It's that rarity that accounts for the luck associated with four-leaf clovers. In other words, you're lucky just to find one, so it stands to reason (a certain kind of reason) that more luck will follow. This is what scholars like to call "magical thinking."

Because of the way our brains operate, we're constantly looking for connections to explain the happenstance of the world around us. Magical thinking kicks in when we refuse to revise our conclusions despite all evidence to the contrary [source: Diaconis].

Take the story of Sandra and her stolen bicycle. Both she and the officer who found it attribute the happy outcome to the four-leaf clover she gave him from her collection. But a skeptic might ask how someone toting a quiver of the lucky clovers would have the misfortune of being robbed of her bike in the first place.

Magical thinking skirts around awkward questions like this and sticks to the convenient details while ignoring the inconvenient ones. That said, in this case at least, magical thinking is a lot more fun than skepticism.

In that spirit, here's a bit of clover trivia: In 2009, after studying ways to crossbreed the lucky plant, a farmer in Japan named Shigeo Obara grew a clover with 56 leaves on it! Logically, that makes it 14 times luckier than a mere four-leaf clover [source: Japan Times].

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.