Dirt made my lunch, dirt made my lunch…. Thank you dirt, thanks a bunch, ‘cuz dirt made my lunch. -Banana Slug String Band

Ask just about any 2nd grader with a Common Threads school garden, and they’ll tell you how important “dirt” is… But what are kids learning about soil?

Digging in the dirt, learning about soil

Common Threads students investigating soil

Soil is the mixture of minerals, water, air, organic matter, and countless organisms. Food is only as healthy as the soil in which it grows. In the fall, Common Threads (with help from our students) took soil samples from each of our school gardens and mailed them to A & L Western Agricultural Laboratories in Portland. The results we received were fascinating!

In general our school gardens are high in organic material, which will decompose over time to provide plants with the nitrogen they need to grow. While most of our gardens have plenty of nitrogen, some need added nitrogen for plants to use this spring. After investigating ways to amend our soils, Common Threads decided to invest in organic flax meal as a kid-friendly fertilizer. 

Testing soil is a great way to get to know your neighborhood in an intimate way. For instance, Harmony Elementary School garden soil displayed sodium levels nearly five times higher than our other schools, which helped us make sense of some unusually purplish brassicas last fall.

Common Threads student examining soil

So much to learn about soil!

Armed with the data from the soil laboratory, Harmony’s garden committee is asking the school district to fund more soil sampling to determine if high sodium comes from the water supply or leaching from the wood used to build the beds. Findings will determine next steps, which might include installing a water filtration system or other type of water treatment, leading to healthier soil at Harmony school.

Fun Fact: Common Threads’ current partner school garden beds comprise a total of 9,537.5 square feet… That’s ¼ an acre of land!