Alameda County Healthy Homes Lead Poisoning Prevention Lead in Soil
This content resides on the Alameda County Healthy Homes Lead Poisoning Prevention Program website
Lead-Safe Urban Gardening
Gardening is a wonderful way to grow local healthy food. There are many benefits. But it's important to make sure that people, especially children, aren't exposed to lead from gardening.
In the Bay Area, soil is often contaminated with lead. Lead poisoning is a serious problem for children because it causes brain damage, behavior problems and other serious health problems. The primary source of lead exposure for adults and children is paint from pre-1978 buildings. Lead dust may be inside a home and outside in the soil. Children should not have contact with contaminated soil in play areas and gardens. See our Lead in Soil page for more information.
There are ways to garden safely. See below for some helpful tips.
Children in the Garden
If your garden is accessible to children, limit their direct contact with the soil, provide hand-washing stations, clean garden toys, don't track dirt inside and wash all vegetables before tasting.
All children should be tested for lead exposure at age one and two, and more often, if necessary. Talk to their doctor about your child's risk level. Go to our Child Safety FAQ page for more information.
Test or assume there is lead in the soil
- Have your soil tested by a state certified lead risk assessor/inspector (PDF - 271kB) or assume it is contaminated and bring in clean soil.
- If you do the testing yourself, follow proper procedures for testing soil and use an accredited laboratory.
- There is no universally-accepted safe level of lead in vegetable garden soil. Below are some general guidelines for interpreting test results. Be aware that test results may vary greatly in different locations within the same yard. It is best to utilize a lead certified risk assessor to do the sampling.
10-50 ppmTypical background level of lead in soil
Less than 300 ppmUniversity of Minnesota: From Lead in the Home Garden and Urban Soil: Safe level for garden produce
400 ppm or greaterFederal and California: Hazard level for bare soil in children's play areas
1000 ppm or greaterCalifornia: Hazard level for bare soil in non-ply areas. Hazardous waste level.
How to Reduce Lead Exposure in a Vegetable Garden
Most urban property has some lead in the soil due to the lead-based paint on buildings built before 1978, prior use of leaded gasoline, and/or industrial emissions. Lead paint that has flaked off or was scraped, sanded or disturbed during renovations any time in the past, may still be contaminating the soil.
Follow these tips for a safer and healthier garden:
- Cover bare soil in beds and in non-growing areas such as pathways to reduce children's exposure to soil, and to reduce soil splash, dust and tracking of soil into the home. Different materials are available such as stones, wood chips, grass, or pavers for paths. Leave gardening shoes outside.
- Carefully choose the garden location. Consider all possible historic sources of lead and other contaminants on your property. Avoid planting in or using soil from locations next to buildings built before 1978.
- Use or build raised beds and bring in new soil. Test soil to ensure a low lead level. Add in new compost or other organic materials often.
- Do not use pressure-treated lumber or painted materials to create the raised beds or greenhouses. Also, avoid use of railroad ties, telephone poles, tires, bathtubs, old painted lumber, old painted windows, or other painted recycled products.
- Maintain a good soil nutrient balance. Plant lead concentrations typically decrease with increasing soil pH. Use of phosphate containing soil amendments such as triple superphosphate can reduce plant uptake of lead.
- Always wash hands after gardening and handling livestock. Children and adults, who play or work in the garden or with livestock should wash their hands often.
- Avoid bringing soil and livestock waste into your home after gardening by washing garden tools and harvested vegetables and changing your shoes before going indoors.
- Thoroughly wash and/or peel garden produce and don't sample from the garden. This is especially important for leafy greens and
- Choosing Crops
- Belowground crops such as potatoes, radishes, beets, carrots take up the most lead. Lead from the soil can also adhere to the skin.
- Leafing crops such as lettuce, kale, and spinach take up some lead and may have lead-containing dust on the edible leaves.
- Aboveground crops such as strawberries, beans, squash, tomatoes, and fruit trees are the least likely to accumulate any lead.
- Home Gardens and Lead; What You Should Know about Growing Plants in Lead Contaminated Soil, University of California Agriculture and Resources (PDF - 590kB)
- Other helpful articles (PDF - 271kB)
- Printable version and other educational materials
The Bay Area has a wealth of resources for urban gardeners.
The Alameda County Master Gardeners Program offers an extensive website at http://acmg.ucdavis.edu plus classes and a Plant Doctor Hotline at 510-639-1371.
Bay Friendly Landscaping and Gardening, www.stopwaste.org offers information, classes, workshops, garden tours, and compost bins.
East Bay Municipal Utility District (EBMUD) www.ebmud.com offers workshops, free on-site water surveys, and rebates for lawn conversions and self adjusting irrigation controllers.
Planting Justice, http://plantingjustice.org offers garden consultations and assistance and can be reached at 510-290-4049.
Lead Hazard Repair Funds Financial and technical assistance for lead hazard repair work may be available for eligible properties with low-income tenants. For more information please call the public Information line at 510-567-8280.