Pairs of tighty whities are being buried in backyards and farms across the nation to check how healthy soil is. 

Key points:

  • The more degraded the cotton underpants are after eight weeks underground, the better the soil quality
  • The experiment has since been launched as a citizen science program
  • Farmers across the country have been getting on board to learn more about their soil’s biology and health

Soil Your Undies is a joint campaign by the University of New England (UNE) and CottonInfo.

The experiment is to bury 100-per-cent cotton underwear for eight weeks and then dig them back up.

The more degraded they are means the better the soil health is as it measures microbial activity.

UNE professor Oliver Knox said they started the experiment at a cotton industry conference after he heard a similar program in Canada. 

“The farmers were over the moon about this competition they now had that looked at their soil biology and their soil health — all based on the degradation of pairs of underpants.” 

Citizen scientists get on board

Dr Knox said since the conference the project had expanded to become a national citizen science campaign. 

Young man with a pale complexion in a bright green embroidered work shirt holds a coat hanger with a pair of degraded long johns

Oliver Knox from the UNE is running the program alongside CottonInfo. (

Supplied: Oliver Knox


“We had people out Christmas Island way, Perth, somewhere in the centre, way up north, down south, all through New South Wales and Victoria and into Queensland,” he said. 

Dr Knox said there was a huge variety in the way underpants degraded during the eight-week period in the soil.

“We’ve had all sorts; [there were] underpants that were just elastic and the polycotton stitching left,” he said.

CottonInfo now hosts a map of Australia locating where underwear has been buried and excavated.

Working with the underground

In Maryborough, Queensland several farmers got their hands dirty with some mixed results.

Cotton grower Scott Maxwell was happy with the quality of his soil.

“It was a good result for here,” he said.

“Only the elastic band was left so I was pretty happy with that.”

Mr Maxwell said what made it more enjoyable was getting his children involved in the experiment. 

“They’re pretty young, so burying a pair of undies and digging them up eight weeks later has a certain attraction to it,” he said. 

A semi decayed pair of white cotton underwear have been dug up and sit in a patch of dirt. The crotch, band and stitching remain

Not much was left after Scott Maxwell and his family buried this pair of undies.(

Supplied: Scott Maxwell 


A young red headed boy squats in a field of unflowered cotton grinning after digging up a pair of undies

Scott Maxwell’s son Travis is helping his dad dig up the underwear they buried.  (

Supplied: Scott Maxwell


For those farmers with poorer results local agronomist Wayne Seiler says there are steps that can be taken.

“We’ll look at what crops we grow there,” he said.

“We might put legume crops in, or green manure or cereal crops with a fibrous root system, and just try to structurally get the soil better.”

Mr Seiler said it gave growers the opportunity to learn about their soil quality to then improve it.

“There was one block that had very little break down and that block had biosolids put on it,” he said.

“That particular area seems to be a very hard-setting soil.

Not too wet or too dry

For the best results, Dr Knox said soil needed to have an optimal moisture content.

He said during drought there was not enough moisture in soil to keep microbes alive.

A small white flag with soil your undies on it sits above a pair of dirty white cotton undies that has barely decomposed

The less left of your undies under burying them, the healthier your soil.   (

Supplied: Scott Maxwell


“A farmer might have buried a pair [of underpants] in a [irrigated] field and then next door in native vegetation,” Dr Knox said.

“The field pair breaks down and the native vegetation pair doesn’t.

“It’s probably good soil but we’ve been gripped in drought for the 2–3 years we’ve been doing this.

Dr Knox said too much water in soil caused there to be little to no oxygen for the microbes to survive.

“We have had some cases of pairs of underpants that were buried and the areas became flooded and the soil became anaerobic,” he said.

“So flooded soil tends to break them [the underwear] down less too.”

Why are farmers and gardeners ‘soiling’ their undies?
Source 1


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