Food & Farming

‘Soil Your Undies’ to Test Health of Your Yard


Northern Rhode Island Conservation District soil conservationist Marina Capraro holds up a pair of underwear she's about to bury at Snake Den Farm in Johnston in May as part of the 'Soil Your Undies Challenge.' (Todd Le/NRICD)

JOHNSTON, R.I. — Got a pair of tighty whities you want to get rid of? Instead of throwing them away, bury them in your yard.

No, really. Bury them in May or June next year, dig them up in about 60 days, and you’ll have an accurate assessment of the microbial activity in your soil.

It’s part of the U.S. Department of Agriculture’s Soil Your Undies Challenge, according to Molly Allard, district manager of the Northern Rhode Island Conservation District.

According to the USDA, your underwear won’t break down in just any soil. It needs healthy soil, which contains billions of microbes, which will eat the cotton. In addition to snacking on organic matter like cotton, microbes also help soil resist erosion, cycle nutrients, and store water.

The underwear must be 100% cotton, Allard said. “Women’s, kids’, or colored cotton underwear should work just as well. The important thing is that they be 100% cotton, not polyester or a blend,” she said. “You’ll notice that the undies’ polyester waistband remained fully intact” when the microbes finish snacking.

Allard also noted that 100% cotton underwear can be pretty hard to find. “The underwear that we used was the only package of 100% cotton underwear that was in stock at Target on the day that I went,” she said.

May and June are the ideal times for planting, because the temperature of the soil is warm enough that the microbes will be awake and ready to nosh.

The USDA recommends burying the undies upright in about a foot of soil, with the waistband left above ground. Make sure the underwear isn’t bunched up. If the soil is dry, add some non-treated water to the underwear plant. Water treated with chlorine or other chemicals will kill the microbes.

a woman holds up a scrap of clothing
Marina Capraro dug up completely deteriorated undies at Snake Den Farm in Johnston this month. (Todd Le/NRICD)

Once you have buried the underwear, wait at least 60 days before digging it up. The microbes need time to get to work.

If, once you dig up the buried underwear, it’s intact, that doesn’t bode well for other plants, Allard said.

“If the underwear doesn’t get eaten, it would mean that the soil microbiome is less active,” she said. “When we’re looking at growing food and plants, a healthy soil microbiome is desirable — so if the experiment is unsuccessful, it may mean that plants would not grow as well in the soil or would need more fertilizer and water to grow.”

In that case, she said, “The same things we recommend that farmers do to keep a healthy soil microbiome work well for home gardeners, too. Minimize soil disturbance (e.g., avoid tilling or digging), keep your soil covered (with mulch or a cover crop like clover), keep living roots growing in your soil all year-round (another great advantage of cover crops), and use plant diversity to increase the diversity of your soil microbes.”

If you want to enter the “Soil Your Undies Challenge,” send a “planting” (before) and a “harvest” (after) photo, along with a little information about the location, to [email protected]. Submissions will be included on the USDA’s  Soil Your Undies Challenge Tracker.


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