Habitat How-To: Solarization for Site Preparation

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Use the power of the sun to control weeds and pests

By Aaron Kuehl, PF & QF Director of Seed Programs

The single most important concept every habitat project manager must know is that site preparation is critical to project success. Fortunately, there are several site preparation techniques a manager can utilize depending on project size, existing vegetation, weed pressure, soil conditions, and access to equipment.

Solarization is a site preparation method which uses the power of the sun to control weeds and pests (bacteria, insects, etc.) in the soil. It does particularly well with control of annual weeds by killing seed. It is less effective on deep-rooted perennial plants or rhizomes in the soil. Solarization is best used on sites which are small, or long and narrow. The method should be used during the summer ahead of a dormant fall or winter frost seeding project. It could also be used ahead of late summer /early fall plantings (i.e. brassica, clover). Some managers who employ the technique do so because it can achieve good weed control organically (without herbicides).  

To solarize your soil:
  1. Clear the area of plants and weeds. This may include mowing or some type of tillage.
  2. Ensure the soil is wet. Soil moisture helps stimulate weed seed germination and improves future heating of the soil.
  3. Dig a 4-inch trench around the perimeter of the project area. For small projects, a spade can suffice, but consider renting a trencher for larger projects.
  4. Cover the area with clear plastic (one-four inches painter’s plastic). Thicker plastics are more resistant to damage but thinner plastics allow more heating of the soil. Do not use black plastic for this type of project, which primarily utilizes shading rather than heating. Bury the plastic edges in your trench and cover with soil.
  5. Leave plastic in place for 4-6 weeks in the summer. Check regularly for damage by wind or wildlife and patch.
  6. Remove the plastic and any dead vegetative material.  
  7. This process can be repeated (steps 2-6) in early, mid, and late summer with a light discing between applications to stimulate additional weed seeds in the soil bank.
If you need more information about solarization, other site preparation techniques, or your habitat project, visit our How-To page or talk to one of our wildlife biologists at 866-914-7373. Think Habitat!

This story originally appeared in the 2022 Spring Issue of the Quail Forever Journal. If you enjoyed it and would like to be the first to read more great upland content like this, become a Quail Forever member today!