002 The dirt on Seattle’s dirt.
What were the geological forces that made the Pacific Northwest so fertile?
0000-1851. Before Seattle was Seattle, what did Pacific Northwest indigenous peoples eat?
Soils from 10,200 feet above sea level look significantly different than soils from 5,000 feet above sea level. I’ll never forget the time I saw dirt from Leadville spilled out on the sand in Farmington when we reassembled our swing set after moving from Colorado to New Mexico in 1978.
Leadville’s soil was loamy and dark, almost black against Farmington’s light grainy sand. Soils, the byproduct of geological forces, are as individual as people and crucial to place and terroir. One of the things that makes Washington state’s soils renowned is their diversity. From the dark, peaty soils in the western half of the state to the lighter, sandier loams of Eastern Washington.1
Washington State’s unique geology was formed over billions of years 2, the result of continents cleaving and colliding, mountains moving and erupting. Water and lava flowing, Ice Age glaciers freezing, creeping, retreating and melting. 3
I’ve been reading about this all week, from Wikipedia pages and natural history websites to books and journal articles, and my head is about to explode! This shit is fascinating. So let me try to sum it all up.
As recently as 16,000 years ago, during a long-ass cold snap otherwise known as the Vashon Glaciation, much of Washington State was covered by the Cordilleran Ice Sheet.4 The advance and retreat of this ice sheet, combined with Mt. Rainier and Mt. Saint Helens5 blowing their tops like screaming toddlers a few times, is what gave us the Washington landscape we know and love. The mountains, the valleys, the rivers, the sound. The marshes and peat bogs. The hills and lakes that make up Seattle’s neighborhoods6:
A mere 17,000 years ago, a massive glacier the height of five Space Needles covered what is now Seattle and a large part of western Washington. It carved out Puget Sound and Lake Washington as it advanced and retreated. And Seattle’s hilly neighborhoods — including Queen Anne, Capitol Hill and Beacon Hill — were etched by the glacier’s icy underbelly.
– Amy Rolph
Incidentally, the product of these geologic forces is some of the richest, most diverse soil in the world. There are 12 soil orders in the U.S., and Washington State contains 10 of them 7. Like state birds and state flowers, some states also have a designated state soil; e.g., a soil of unique significance to the state. Washington was the first state in the union to name an Andisol as its state soil – coined Tokul soil after a small community and creek about an hour east of Seattle in the Cascade Mountains.
Tokul soils are among the most productive soils in the world. These soils support Douglas-fir and other conifer trees, which are the source of Washington’s nickname, the Evergreen State. The State of Washington has hundreds of soils that are influenced by volcanic ash. These volcanic soils are used for crop production, timber production, livestock grazing, recreation, and watershed. Most areas of Tokul soils are used for timber production, but some of the smaller areas are used as pasture and for urban development. [W]ater perches above the dense glacial till during wet periods, making steep slopes unstable. 8
and
The Tokul soil series is very unique. Parent material is volcanic ash and loess over glacial till. Tokul soils are generally found on lowland plains and glacially modified hills and mountains. Native vegetation is Douglas-fir, western hemlock and western red cedar. The understory generally consists of western Swordfern, vine maple, huckleberry, trailing blackberry, and Oregon grape. 9
Washington’s soils and climate make it one of the most productive agricultural states in the union.
– by Kara Rowe in Agriculture in Washington, 1792 to 1900
There is so much I could write here about soils. I could go on and on. About how the soils in northwestern Washington are much younger than the soils in the southern part of the state because they were covered with glaciers while southern soils were not. About how volcanic ash is found in soils all over the state, all the way east to Spokane. About how dirt is not just dirt, this inanimate thing that we walk on, drive over, dig into, pave over. Dirt is not just dirt. It is soil and soil is a living organism, just like the humans, plants, and animals that live on it and in it. If we want to protect our food sources, we need to protect our soils.
So suffice it to say that part of what makes Seattle’s food so good – a very large part – are the soils provided to us by glaciers and volcanos 10. We owe our ancient ice and fire a lot!
Next Up
What’s weather got to do with it? How do Seattle’s clouds, rain, and showers contribute to our great food?
One time at a party, Will compared notes with a friend of mine on eating dirt as kids. Have you ever eaten dirt? If so, do tell (I haven’t, by the way)!
Food is about dialogue. Let’s start a conversation.