Gardening Safely in Soil That May Contain Lead

Raised beds filled with clean soil are one of the best protections. Image from the EPA.

Lead in soil is dangerous, above all to children and to women who are pregnant or breastfeeding, who are more sensitive to its effects. But a garden in a possibly contaminated yard can still be a safe place to grow food — and gardening can even help: eating fruit and vegetables and getting exercise are part of a healthy life, and studies show that a well-nourished child absorbs less lead. The single best step, says the EPA, is to grow in raised beds filled with clean soil.

How gardeners are exposed

• Eating produce that has absorbed lead from the soil.
• Eating produce with contaminated soil still on it.
• Tracking soil indoors on shoes, clothes or tools.
• Swallowing or breathing contaminated dust or dirt while gardening.

Four ways lead in soil can reach people. Image from the EPA.

Test your soil first

Knowing how much lead is in your soil lets you choose how to garden. Some local health departments offer home soil testing; most laboratories linked to state university agriculture departments and extension offices test soil; and CDC's soilSHOP events screen garden soil for lead and other contaminants. Results come in milligrams per kilogram or parts per million, which are the same thing: 100 ppm is 100 mg/kg.

Good habits in any garden

While working: wear gloves; wash hands, clothes, tools, toys and pacifiers afterwards; keep children and pets out if the lead level is unknown; store tools outside the living areas; take shoes off at the door; clean floors regularly.

Preparing the garden: mulch to keep down dust and keep soil off crops; build raised beds of clean soil over a visible barrier such as garden fabric, or grow in containers; site the garden away from sources of lead such as old painted buildings and busy roads; bring in compost or manure from outside; keep the soil pH near neutral, 6.5 to 7.5, to limit how much lead plants take up; and ask an extension office about other soil amendments.

In the kitchen: discard the outer leaves of leafy vegetables, wash all produce, and peel root crops such as carrots, beets, turnips and radishes.

What to plant, by lead level

Approaching 200 ppm — take care. Follow the good habits above, and limit gardening if you are pregnant or nursing. Root vegetables and shallow-rooted plants such as lettuce can grow in the existing soil; plants with deep roots, such as tomatoes, belong in raised beds.

200 to 400 ppm — change the soil. Use raised beds of clean soil with compost or manure, cover bare soil with ground cover or mulch, and peel root vegetables. Grow root vegetables and shallow-rooted plants in raised beds; deep-rooted plants are not recommended even there, unless grown in containers.

Shallow-rooted plants such as lettuce do well in raised beds of clean soil. Image from the EPA.

Over 400 ppm — do not use the existing soil. Grow only shallow-rooted plants, in raised beds with at least 16 inches of clean soil on garden fabric, or in containers. Keep bare soil covered or damp, and add clean soil and compost every year. Root vegetables and deep-rooted plants are not recommended except in containers.

Sources

• U.S. Environmental Protection Agency, "Healthy Gardening Practices to Reduce Exposure to Lead-Contaminated Soil"; rewritten in hubnx's own words. Images from the EPA. See also the EPA's page on lead in soil and the Agency for Toxic Substances and Disease Registry's guidance on soil, gardening and health.