Soap nuts have always seemed a little hippy-dippy to me. I mean, washing your clothes with nuts? But my friend Jen suggested I check them out, so I thought, why not? and got a sample pack.

This sample pack washes 16 loads of laundry.

First off, they’re not nuts; they’re dried fruit from the sapindus tree (which is why they’re also known as soap berries). When they’re heated, they secrete saponin, a natural surfactant. They’re perfect for front-loading washing machines, because they’re low-sudsing.

Now, we currently wash out clothes in cold water, and switching to warm water wouldn’t make much environmental sense. But you can boil the soap nuts on the stovetop to create detergent. Just bring 4 cups of water to a boil, turn it off, and toss in 6–8 soap nuts. Soak overnight, fish the soap nuts out in the morning, and filter. At 1/4 to 1/2 cup for each load of laundry, it’s actually more efficient this way than throwing the soap nuts in a warm water wash.

The prepared detergent

Even better—it’s cheaper than the Tide HE Free that we were using before. That washed 64 loads for $14. A pound of soap nuts should wash (at least) 175 loads for $30.

Granted, they’re shipped from the Himalayas, but the dried-out fruit is really light—much lighter than bottles of laundry detergent. And, at least from Laundry Tree, they come in paper bags and cardboard boxes—no plastic in sight.

I can’t believe what an unmitigated success this experiment was. I vow to be more open-minded in the future.

One year ago: An Explosion of Worms . . . and Flies