Soil Testing

One of the first steps we took before laying out the Roots & Wings labyrinth, on the front lawn of South Church, was to test the soil. The most common tests to have done are the nutrient levels—particularly the pH—and for heavy metals like lead.

Sheet mulching involves creating layers above the grass.

We decided to just do the nutrient level test as we were sheet mulching and the plants' roots would not touch the existing soil.

WHERE TO HAVE SOIL TESTING DONE

• We used Agro-One Services to test the specific soil on South’s front lawn for nutrients (they can also test for heavy metals).  You can obtain forms and directions here or pick up sample boxes and forms at Cornell Cooperative Extension of Westchester County, 26 Legion Drive, Valhalla, NY 10595. The boxes and forms are free, the test is about $10.

• Lea Culled-Boyer, Hastings resident and Managing Director of the Green Guru Network, recommends Environmental Working Group to test for heavy metals and Westchester County’s own testing facilities. She says, “EWG's tests are more affordable.”

• Susan DeGeorge, Roots & Wings member, recommends websoilsurvey.nrcs.usda.gov. She says, “This gives the geological history of an area, different soil horizons in the area, parent material that the soil is made from, how far down the water table is, etc.”

WHAT WE FOUND OUT

• Our pH level is excellent, at 6.3, and everything else looks fine.

BUT WHAT ABOUT THE HEAVY METALS?

Some of us still wondered about the possible presence of lead and the aluminum that showed up in the soil (too much active aluminum can kill plants by inhibiting root growth).

Susan asked her soil science teacher David Bulpitt who is both a soil instructor at the New York Botanical Gardens and a  principal of Brookside Nurseries in Norwalk (which specializes in soil and soil mixes for horticultural uses). Here's what she learned.

“For aluminum: a pH above 5.5-6. or so should take care of the problem since it can't be water soluble in a neutral or alkaline soil.  For heavy metals (lead, etc.) a higher pH also means they're less soluble.   Applying that to our soil sample, I think that means we should be okay as long as we keep the pH where it is (since it's just a little above 6).  We need to watch doing things that could lower the pH though."

If you have additional questions regarding soil testing procedures, contact Jerry Giordano at Cornell University Cooperative Extension of Westchester County at westchester@cornell.edu. You may also contact Agro-One directly through Dairy One at 1-800-344-2697 x 2179 or x 2172 or email mark.joyce@dairyone.com.