King County promotes the importance of healthy soil

Construction standards improve soils, help preserve the environment

Healthy soil helps protect the environment and ensures beautiful lawns and gardens. King County is helping to improve soils by implementing post-construction standards on soil depth and quality in unincorporated areas. Other local governments in western Washington will follow suit with similar standards before 2010.

"Like clean air and clean water, healthy soil is vital for a healthy environment,"said Theresa Jennings, acting director of King County's Department of Natural Resources and Parks. "Preserving soil or restoring it in disturbed areas such as construction sites is essential to managing stormwater runoff and preventing water pollution."

Healthy soil not only allows vegetation to flourish, but protects the environment by absorbing excess rainwater and preventing flooding. Acting like a sponge, deep, rich soil releases water to plants between rainfalls. Water is cleaned as it percolates through the soil, preserving water quality and protecting the people and wildlife that depend on it.

"This is also good news for gardeners," said Sharon Aller of the King County Solid Waste Division. "Healthy soil reduces the need to irrigate and fertilize, and it protects plants from pests and diseases, which makes it easier to maintain landscapes."

King County's post-construction soil standard, which has been in effect since 2005, requires a minimum of eight inches of soil containing 8-13 percent of the soil organic matter that provides food for worms and other soil life. Cities and counties across western Washington will be updating their stormwater regulations over the next 18 months to include soil best management practices, as required by the State Department of Ecology.

Stephanie Warden, director of King County's Department of Development and Environmental Services, said establishing minimum thresholds for soil depth and quality is a significant improvement in land development practices, considering that traditional practices can damage valuable soil functions by removing or compacting topsoil.

"While King County is one of the first communities in the country to have requirements for soil management in place, we're encouraged to know than other communities will be joining with similar standards, which will support a healthier environment across the region," Warden said.

"Building or maintaining healthy soil doesn't have to be difficult, time consuming or expensive," Aller added.

"King County recommends practicing natural yard care, including using compost and mulch, and other natural yard care practices for the best results."

Tips to improve and maintain soil quality include:

• Mixing up to three inches of compost into planting beds in the spring;
• For lawns in poor condition, sprinkle with ½ inch of compost in the spring;
• Leave grass clippings on the lawn to add moisture and nutrients;
• Use the least toxic solution to pest and weed problems;
• When using fertilizer, opt for the "natural organic"or "slow release"variety; and
• Apply mulch over the soil's surface to retain water and prevent weeds.
  

More information on building healthy soil is available at http://www.metrokc.gov/dnrp/swd/soils/.