When to Amend?

The goal: healthy soil under every landscape Washington State DOE’s stormwater BMP T5.13 “Post Construction Soil Quality and Depth” requires that every construction site be left with at least 12 inches of un-compacted soil, and that the upper 8 inches have sufficient organic content to support a healthy landscape and soak up most rainfall.

5 Steps to Building Healthy Soil

Best management practices (BMPs) during construction:

1. Retain and protect native topsoil & vegetation where practical

2. Restore construction-disturbed soils, to restore healthy soil functions, by:

• Stockpiling & reusing good quality site soil, or

• Tilling 2-3" of compost into poor site soils, or

• Bringing in 8" of compost-amended topsoil.

3. Loosen compacted subsoil, if needed, by ripping to 12" depth

4. Mulch landscape beds after planting

5. Protect restored soils from erosion or re-compaction by heavy equipment