Tighty Whitie Soil Test – A Brief Review

Home » Blog » Tighty Whitie Soil Test – A Brief Review

Robert Pavlis

The tighty whitie soil test is a great way to measure soil health and demonstrate the value of no-till gardening.

In this post, I will have a brief look at the science behind the test.

Tighty Whitie Soil Test - measures the microbe population in your soil
Tighty Whitie Soil Test – measures the microbe population in your soil

Tighty Whitie Soil Test

Healthy soil contains a lot of microbes that need organic matter as a food source, but how can the homeowner measure the level of organic matter? Professional soil tests are expensive and require complicated equipment which is not suitable for DIY gardeners. This is no longer a problem. The tighty whitie soil test can be done by anyone and requires no equipment.

Take some white cotton underwear, weight it and bury it in the garden. Your frilly silk panties may work in the bedroom, but not for this test. And don’t use thongs – they just don’t provide enough organic matter to give an accurate weight.

Warning: it is best to remove the tighty whitie before you bury it.

After 5 weeks, remove the underwear, and weigh it. How much of the cotton was consumed by the microbes?

If most of it is still there, your soil is not very healthy and you need to add compost. If you are left with the elastic, congratulations, your soil is in peak condition.

Plant Science for Gardeners by Robert Pavlis

Scholars Reveal All

The tighty whitie test was conducted by the South Dakota Soil Health Coalition’s first Soil Health School to compare no-till with tilling. The results are presented in the table below.

Clearly, no-till has the healthiest soil (second from the left in the above picture). Less disturbance of the soil results in more microbes which in turn makes it healthier.

Tilled soil (far right in the picture) destroys, not only soil structure but also the life in the soil.

Tighty Whitie Soil Test - measures the microbe population in your soil

Thanks for this Great Idea

This great soil test was developed by Anthony Bly and Sara Berg of South Dakota State University Extension. It was put into print by  Kathy Voth, in On Pasture. Photo and table have been used by permission.

Thanks to these people for making gardening fun, and thanks to the gentlemen for posing in the picture.

If you like this post, please share .......

Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

7 thoughts on “Tighty Whitie Soil Test – A Brief Review”

  1. I buried an old white sleeveless T Shirt in a raised bed filled with compost. The bed and compost are approximately 5 years old. I left the T Shirt buried in the bed for 7 weeks. When I dug it up it didn’t have a single hole in it. It looked the same as when it was buried, just much dirtier.

  2. Thanks for the reply. It would look bad if I had to move out and the new owners found these laying around. But joking aside, the yard has heavy compacted clay soil, and I’m looking for ways to loosen/open/break up the clay wherever I can. I wonder if the larger ‘particle size’ of the cotton fibers can help in this regard (by their physical presence alone, plus providing food for microbial growth).

    • Your soil needs lots of organic matter at this point. The microbes will make good soil once they get fed with the organic matter.

  3. Very interesting, thanks for passing along. Question: I moved into a new subdivision with heavy clay soil in south central Texas. I have about a hundred old hole-y white socks and underwear (labelled 100% cotton on the original packages) that are relegated to the ‘ragbag’. Could these be used to add organic material to the soil in my backyard, or help break up the clay over the long term? I envision spreading them in shallow holes or trenches to be used for future planting. I would cover them loosely with some soil, periodically inspect the progress, and eventually pull out the elastic bands and other visible leftovers. I expect it’d take more than 5 months, but I’m not in a hurry. I’d wash the underpants one last time to kill fecal coliforms. Sound reasonable (or practical)? Or maybe it’d be better to just cut them in half and put in compost bin?


Please leave a comment either here or in our Facebook Group: Garden Fundamentals