The Deschutes Land Trust recently started the third year of a native plant restoration project in the Hindman Springs portion of Camp Polk Meadow Preserve. For several years, we've been using a process called soil solarization to remove weeds and prepare for native plantings.
Soil solarization is the process of using the sun's powerful energy to bake the soil under a layer of plastic to kill a pest or weed. In this case, the Land Trust is working to kill weeds and weed seeds that have been in the soil for 150 years! Solarization, while labor intensive, is an effective way to kill weeds and suppress germination of weed seeds far longer than many herbicides.
Before we can lay the plastic on the soil, however, we have to prepare the soil. This spring Jen Zalewski and Peter Cooper were at the Preserve (6 ft. apart, of course!) to prepare the ground for solarization. First, they tilled the soil to remove old weeds and break up the soil. Tilled soil has more air pockets that will allow the heat (that will eventually collect under the plastic) to penetrate more deeply. Then, they raked out the soil to eliminate bumps and ridges. Finally, they used a trencher to make a trench all the way around the solarization area. Once the plastic is put in place, Jen and Peter will tuck the edges of the plastic into this trench and then bury the edges with soil. We've found trenching and burying the plastic to be the best way to keep the plastic in place for the several months that solarization requires. Watch the video below to learn more about this process!
In the next several weeks staff will return to Camp Polk Meadow Preserve to lay out the clear plastic that will bake those weeds and weed seeds all summer long. Then, we will return this fall to plant lots of new native grasses, shrubs, and wildflowers. The end goal is to give the native plants that would have historically been at Hindman Springs a chance to thrive into the future. Stay tuned!
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