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The Undies of 2022 have been planted! 

125 pairs of brand-new, 100% cotton undies are now marinating underground at 73 residences across Lake Oswego. These will be dug up in July and evaluated according to how much was eaten away by active soil critters. 

Read below for more information about the Soil Your Undies challenge and the information about soil health we hope to glean from our second year of this community soil science experiment!


Participants of Soil Your Undies 2022:

We’ll be sending a biweekly soil column that will contain handy info about soil quality, soil’s relationship to climate change mitigation and tips on how to make those vital soil microorganisms happy and healthy.

RSVP for “Reveal Your Undies”!
Wednesday, July 13th
5pm-7pm at West Waluga Park!

“Reveal Your Undies!” is our open house event for our Soil Your Undies participants to show off what’s left of the undies they unburied after 60 days of decomposing underground! We’ll have a clothesline to hang up the scraps of undies, family friendly soil science activities and a table for questions about soil health!

OLWC’s 2nd Annual Soil Your Undies Challenge!

Soil Your Undies with OLWC  - Spring 2022
Photo Credit: Hitomi Kawashita

We learned so much about the health of Lake Oswego soil from last year’s Soil Your Undies event that Oswego Lake Watershed Council embarked on the challenge again this spring and with both new and returning participants!

The directions are simple: All you have to do is bury a brand-new pair of 100% cotton underwear under at least 6 inches of soil, wait 60 days, and then dig them back up! The more your undies break down while buried in the soil, the more active the biological community in your soil is!


LOSN/OLWC Virtual Soil Forum featuring David Montgomery

Date: April 14th, 2022

David R. Montgomery, a leading expert, author, and researcher on soil health, spoke about the revolution in soil management and its connection to our food.

David Montgomery

David R. Montgomery

"What Your Food Ate' by Dr. David Montomery

Soil Your Undies Kickoff at the Lake Oswego Sustainability Resource Fair

Date: Sunday, April 24th 11am-2pm

Summary: In celebration of Earth Day, the City of Lake Oswego’s Sustainability Advisory Board is partnering with the Lake Oswego School District, Lake Oswego Sustainability Network, and Oswego Lake Watershed Council held the first annual Lake Oswego Sustainability Resource Fair. We had a blast connecting with you over soil health! Thank you to everyone who attended and participated in this educational community event around natural resource protection and sustainability. 

Soil Your Undies 2021!

Click to download a .pdf of this infographic
Click to download this infographic as a .pdf file

Goals of OLWC’s “Soil Your Undies” Campaign

  • Develop community understanding of the importance of microorganisms to healthy soils:
    – Find out what role healthy soil plays in creating a healthy forest.
    – Learn about the microscopic organisms that break down organic material for food, returning vital nutrients back to the ecosystem.
  • Develop community understanding of the importance of soil in carbon sequestration.
  • Encourage the community to embrace development and maintenance of healthy, living soils as a community climate action.
  • Create a long term soil data collection to observe Lake Oswego’s soil quality over time.

The more your undies break down while buried in the soil, the more active the biological community in your soil is!

Soil Health demo using undies

During OLWC’s Soil Your Undies campaign, we encourage participants to engage with their community online via Facebook and Instagram  to learn more about soil health. 

After July 7th’s Reveal Your Undies event, we will share a report on our website that contains soil testing results, before and after photos of your undies and reflective writings about the project.

We have created easy-to-use instructions, online and printable data sheets to log conditions where the undies were buried.

We encourage our community to share their before and after photos of the underwear using #SoilYourUndies #LOBuriedTreasure #LOBriefs #OLWC, or by sending an email to

Soil Your Undies Campaign

It’s Time to Bury Those Undies!

We know you have questions! Click on a topic below to get started.

How Do I Properly Bury My Undies?

It’s easy! First, make sure that the undies you are burying are undyed and made of 100% cotton. It is important to have something that is not 100% cotton attached (the elastic waist band in undies will work just fine) in case you have really active soil- you want something attached that will not be easily eaten by microbes in the soil. Once you have the appropriate materials, it is time to say goodbye to those undies for two months.

We also want to gather some information about where you bury your undies and how you take care of your garden. Collecting this data will help us track changes as we all work to develop healthy soils. We will be creating a community-wide Soil Your Undies map and will be keeping track of the data , so please share information about your undies by visiting THIS ONLINE FORM, or downloading THIS PRINTABLE FORM. If you elect to use the printable data sheet, please email the results to

Here are some tips to make your experiment a success:

  • Bury your undies in approximately 6-8 inches of soil. This is the root zone, where most of the biological activities occur.
  • Lay the undies flat in the hole you buried – avoid any crumpling or wrinkling.
  • Take a photo in the hole before you cover them with dirt. Don’t forget to share photos with us on social media using #LOUndies #ClackBriefs #OLWCUndies #LOBriefs and #SoilYourUndies. You can also email your photo to 
  • Mark the site so you can find it again. THIS IS REALLY IMPORTANT!
  • Check on your site at least once a week, without unburying the undies. If the soil looks dry, you may need to water the area. Water the area as needed to keep the soil moist, Make sure to document when you water the soil where you buried your undies.

Now that you have buried your undies, it is time to mark the date you will unbury the undies on your calendar! Wait at least 2 months (approximately 60 days) before digging up the soiled underwear. OLWC will be sending out a reminder email 2 months from now to all participants.  We are planning a Reveal Your Undies event for July 7, 2021.  We’ll be sharing details in June.

Can't make the Reveal Your Undies event?

We still want to see your results! Email to arrange a different way of picking up your undies and soil sample or to simply send us a photo of your undies and a short description of your experience.

What’s Happening in My Soil?

In healthy soil, there are millions of microscopic organisms that break down and eat organic material (such as leaves, decaying plants or animals, or 100% cotton underwear) over time. Think of how leaves that fall onto the ground during the Fall season seem to disappear before Spring arrives- that is because many of the leaves have been digested by tiny insects and other microorganisms. Cotton is an organic material (it comes from a plant!), so this process is what will “soil” your cotton undies while they are buried. The more your undies disappear underground before you dig them up in 2 months, the more active your soil’s microbes are

Why Should I Care About my Soiled Undies?

If you pull up ragged undies full of holes after 2 months of being buried, you have healthy soil. There are many benefits to keeping healthy soil, here are just a few:

  • Active microbes in healthy soil provide nutrients needed by plants. This means that having a healthy soil will make it easier for plants to thrive in your garden without adding additional fertilizer.
  • Soil with high amounts of organic matter can hold more water, which prevents excess runoff and increases the soil’s resilience to drought. According to the US Department of Agriculture’s Natural Resources Conservation Service (USDA NRCS), organic matter can hold 18-20 times its weight in water!
  • Soil with high amounts of organic matter can help mitigate climate change by removing CO2 from the atmosphere and storing it in a carbon “pool” (carbon sequestration).