Screen garden soils for lead

Whether you are new to gardening or have been growing your own vegetables for years, you probably understand the importance of getting your soil tested for nutrient levels and soil pH.

But have you ever thought about having your garden soil screened for lead?

Although this bluish-gray metal occurs naturally in soil in small amounts, typically less than 41 parts per million (ppm), higher levels in garden soils may necessitate a range of actions to limit exposure, especially among children who are at increased risks to the health effects of lead.

If you live in the Burlington or Rutland area, you can have your garden soil screened for lead for free at one of the upcoming walk-in clinics called SoilSHOPs, thanks to a partnership among the University of Vermont Extension Master Gardener program, Agency for Toxic Substances and Disease Registry and the U.S. Department of Agriculture Natural Resources Conservation Service.

The first clinic will be held on May 25 from 10 a.m. to 2 p.m. at the University of Vermont Horticulture Research Center, 65 Green Mountain Drive, South Burlington, in collaboration with the Friends of the Hort Farm’s Bloom Time Festival.

Or bring your soil sample to the Godnick Adult Center, 1 Deer St. in Rutland on June 1, 9 a.m.-noon. This event will be held in conjunction with the annual plant sale by the Rutland chapter of the master gardener program.
Visit to learn more. You do not need to register in advance. There is a limit of three samples per family. Trained volunteer health educators will be on site at these walk-in clinics to provide detailed information based on screening results.

You only need to collect one sample from a large garden. If you have multiple, edible gardens in different locations, sample these separately. Note that for soil lead screening, ornamental flower gardens do not need to be tested unless they include edible plants.  

You can also submit a soil sample to the University of Vermont Extension agricultural and environmental testing lab. The lab will run a basic soil test for $17, which provides information on pH, available macronutrients and micronutrients, organic matter and other soil components, along with fertility and lime recommendations.

A heavy metals test (including lead) is available as an add-on or on its own for $15. Results include possible management options if needed.

So, how do you take a soil sample?

If sampling a large area, collect soil from 5-10 random spots throughout the area. For small beds, choose three spots at random.

Dig down to 6-8 inches deep in each location, and then combine the soil samples in a clean container. Be sure to remove any pebbles, roots or other debris.

You will need to let the sample air dry. Do not use a hair dryer, oven or flame. Once dry, scoop 1-2 cups of the mixed soil and transfer to a clean one-quart zipper or slider storage bag.

Wear gloves when collecting your soil sample. If taking more than one sample, rinse your shovel and container between samples. For multiple samples, label each bag so you know which test results apply to which area.
For questions about soils, soil testing and gardening topics, contact the master gardener helpline. Helpline volunteers also are available to take phone calls on Thursdays, 9 a.m.-noon through Oct. 31 at 802-656-5421.

(Debra Heleba is community horticulture program director for the University of Vermont Extension.)