Growing  Gardens   in   Urban  Soils
This fact sheet provides communities and individuals with general
urban gardening information about:

•  Common contaminants that can be found in urban soil.
•  Ways to identify contaminants and reduce exposure.
•  Improving soils and growing plants in mildly contaminated soil.
•  Additional resources and technical assistance.


Communities  throughout the  country are  turning to urban agriculture and
gardening as a reasonable option to increase their access to healthy, nutritious, and
low-cost produce. Some of the sites that communities are using for urban gardens
were previously home to industrial and commercial operations.  A garden on
abandoned land can become a new community asset by improving the visual look
of a neighborhood and potentially increasing nearby property values. Community
gardens provide many benefits, including healthier lifestyles by increasing activity
levels, providing fresh produce, growing community pride, and nurturing social
interactions and cooperation among people.

For communities interested in gardening on a site that might be contaminated, it is
important to first determine the health and suitability of the soil at the site. It is a
common gardening practice to test soil for characteristics such as pH and nutrient
availability.  When creating a garden on land with an industrial or commercial
history, it is highly recommended that communities consider the site's land use
history and test the soil accordingly for potential contamination. Knowledge of soil
health and potential contamination are keys to helping communities identify and
correct problems so that each urban garden is safe and productive.

The possibility of contamination at a garden site should not keep you from planning
an urban garden there. This fact sheet presents steps that you can take to find out
and address potential contamination at your site to help create a safe and healthy
garden for your community.

        U.S. Environmental Protection Agency
        Office of Superfund Remediation and Technology Innovation
   gardener on soil science, soil
amendments, plants, contaminants
   and their health effects, and
additional links is available on EPA's
 CLU-IN website:

So/7  Quality
Q:     Why Is Healthy Soil Important for Your Garden?
A:     Healthy soil is essential for plants to grow in  your garden. When a
       property has been  used for  industrial or commercial  activities, the
       soil  is often  nutrient deficient,  highly  compacted and  potentially
       contaminated. These soils can be improved and made healthy again
       so that your garden plants can grow and  thrive.  Healthy soil  holds
       water and contains  beneficial organisms, plant nutrients, and organic

Soil  Nutrients
Soil nutrients are vital  for healthy soil and must be available for plants to grow.
Soil tests will help you determine the existing nutrients available in your soil and
indicate which nutrients and nutrient amounts need to  be added. Mineral nutrients
such as nitrogen, phosphorus, potassium (NPK), and calcium can occur naturally
in the soil, but often need to be applied to maintain a healthy balance. Soil nutrients
may be added in various forms, including: fertilizer and lime (available in most
gardening stores) and organic matter such as grass clippings, leaves, and compost.

Physical Properties of Soil
The physical properties of soil determine how well nutrients are available to plants.
Soil contains a combination of sand, rock, silt, clay, air, and organic matter, which
affects its ability to hold nutrients and water.

You can improve the physical quality of your soil by leveling and loosening the
soil and adding organic matter such as compost and manure. These additions can
increase the amount of water that sandy soils can absorb or hold and can improve
the drainage of clay soils.

Soil  pH
Soil pH affects the amounts and types of nutrients available to plants through their
roots. The pH scale goes from 0 to 14; a pH of 7 is neutral. A lower number means
a more acidic soil, while a higher number means a more basic or alkaline soil.
Certain nutrients are less available to plants in soils
where the pH is too low or too high. When a soil's pH
is near neutral, nutrients are more readily available to
plants, and microbial populations in the soil increase.
A soil test will tell you the pH of your soil. Based on
this information, you will be able to determine whether
soil amendments (soil additions) are needed to change
the pH of your soil to meet your gardening needs. You
can raise the pH of soil by adding lime or wood ash.
You can lower the pH  of soil  to make  it more acidic
by using fertilizers  containing ammonium-nitrate or
specialty fertilizers for "acid-loving" plants that contain
ammonium sulfate or sulfur-coated urea.

For more information on amendments that can be used
to improve soil quality,  see Techniques for Addressing
Soil Contamination in the Resources section in this fact
sheet, page 11.
pH Scale

A soil contaminant is an element or chemical present in the soil at a level that could possibly
pose health risks. In a few areas of the country, element levels may be naturally high. In many
cases, human activities have increased the soil levels of many elements and chemicals and
also spread them out more widely. Lead, cadmium, arsenic, zinc, and polycyclic aromatic
hydrocarbons (PAHs) are contaminants commonly  found in any urban environment.  In
addition, other contaminants can also be found in areas near former commercial or industrial
properties. Table 1 lists sources of contamination that are commonly found on sites with a
commercial or industrial history.
Table 1. Common Sources of Contamination
General Source
Paint (before 1978)
High traffic areas
Treated lumber
Burning wastes
Contaminated manure
Coal ash
Sewage sludge
Petroleum spills
Examples of Previous Site Uses
Old residential buildings; mining; leather
tanning; landfill operations; aircraft com-
ponent manufacturing
Next to heavily trafficked roadways or
highways; near roadways built before
leaded fuel was phased out
Lumber treatment facilities
Landfill operations
Copper and zinc salts added to animal
Coal-fired power plants; landfills
Sewage treatment plants; agriculture
Gas stations; residential/commercial/in-
dustrial uses (anywhere an aboveground
or underground storage tank is or has
been located)
Widespread pesticide use, such as in
orchards; pesticide formulation, packag-
ing and shipping
Commercial/industrial site use
Dry cleaners
Metal finishing operations
Specific Contaminants
Lead, zinc, polycyclic aromatic hydrocar-
bons (PAHs)
Arsenic, chromium, copper
PAHs, dioxins
Copper, zinc
Molybdenum, sulfur
Cadmium, copper, zinc, lead, persistent
bioaccumulative toxins (PBTs)
PAHs, benzene, toluene, xylene, ethyl
Lead, arsenic, mercury, chlordane and other
chlorinated pesticides
PAHs, petroleum products, solvents, lead,
other heavy metals (such as arsenic, cad-
mium, chromium, lead, mercury and zinc)
Stoddard solvent and tetrachloroethene
Metals and cyanides
 EPA's Toxic Release Inventory (TRI) can provide information to communities about sites where contaminants were
 released into the environment. The Envirofacts database allows users to enter location information, such as zip code,
 address or county location, to get information about releases in their area. The database is available online at: www.
     Adapted from Heinegg, A., Maragos, P., Mason, E., Rabinowicz, J., Straccini, G. and Walsh, H. (2000) Urban Agriculture and Soil
     Contamination, available at:
Are Soil

Background  levels  are
the  naturally occurring
levels  of elements  and
chemicals found in  any
soil. Background levels
differ depending on the
region of the country in
which you live.  In some
areas background levels
for certain elements  and
chemicals may be higher.
Contact    your   local
extension service or state
environmental    agency
(see Technical Assistance
in the Resources section,
page  10)  for   help  in
learning  more   about
elemental   background
levels for the soil in your

More   information   on
soil  background  levels
in the United States is
available  at:  http://pubs.

   Contaminants  continued

 Q: How Do I  Know if My Property is Contaminated?
A: You can conduct a formal environmental assessment (study) of the land you are
   interested  in using for urban gardening. There are two types of assessments:
   Phase  I and Phase  II  Environmental Assessments.  A  Phase  I  assessment
   includes a review by a trained  environmental professional of historical  site
   uses, interviews with neighbors and,  if possible, site owners, and a visual site
   inspection  to determine the potential for and type of contamination at a site. If
   a Phase I assessment determines that there is potential for contamination at the
   site, a Phase II assessment is conducted to sample for contaminants and locate
   any impacted areas.

   For more  information  on Phase 1 and Phase 2  assessments, contact  your local
    and state environmental agencies. Some local governments may even be able to
     provide you with  a Phase  I or Phase II environmental assessment or have qualified
      environmental professionals on staff who can conduct the assessment.

       Q: What if  My Community Needs Help with Site Assessments, Sampling or
         A: Federal funding is available to government entities to conduct
          brownfields (property where reuse may be complicated due to on-site
           contamination) assessments. Working with local officials to apply for
           an EPA brownfields grant can provide  money for your community
             to assess or clean up the property you are  interested in as well as
              address other properties.

               What you need to know to get started  in  applying for brownfields
               grants can be found at:


                    Biosolids are the nutrient-rich organic materials resulting from
                    the treatment of sewage sludge (the name for the solid, semi-
                     solid or liquid untreated residue generated during the treatment
                      of domestic sewage in a treatment facility). When treated
                      and processed, sewage sludge becomes biosolids, which are
                      tested for safety to be recycled and applied as fertilizer to
                       improve and maintain productive soils and stimulate plant
                        growth. Only biosolids  that meet the strictest state and
                        federal standards can be approved for use as a fertilizer.

                        More information on how biosolids have been used to solve
                        problems on potentially contaminated lands is available at:

                        More information on biosolids is available at:
                            More information for the urban gardener on soil science,
                            effects, and additional links is available on EPA's CLU-IN

  Exposure Pathways
  Q:     How Could I Come into Contact with Contaminants while
  A:     An exposure  pathway is  the  way that a contaminant comes into
         contact with people. If a site assessment concludes that contaminants
         are present,  the next step is  to think  about potential contaminant
         impacts as you work the soil to garden or  eat the food you grow.
         There are two human exposure pathways to soil contaminants: the
         soil-to-human pathway and the soil-to-plant-to-human pathway.

  Soil-to-Human Exposure Pathway
  While gardening, the greatest risk of exposure to contaminants is from contaminated
  soil getting into  your mouth or by  breathing in contaminated dust. For  example,
  children playing in the garden may directly eat soil through hand-to-mouth play, or
  people may eat plants without first washing them to remove soil and dust. Skin contact
  (dermal exposure) with soils containing contaminants such as PAHs, chromium and
  trichloroethylene (TCE) can pose health risks.

  Soil-to-Plant-to-Human  Exposure  Pathway
  Some edible  plants do take up and accumulate contaminants. A plant's uptake of
  contaminants depends on many factors, including the type of plant and the pH and
  organic content of the  soil. However, research  shows that there is minimal risk of
  exposure from eating plants grown  in contaminated soils. To reduce concerns of
  exposure from eating  plants, wash produce thoroughly before  eating to remove
  potential soil contamination. Root vegetables have a higher potential for accumulating
  contaminants. In some cases, it may be prudent to avoid growing edible plants in soils
  with high contaminant concentrations.
     What Are EPA Soil Screening  Levels  (SSLs)  and Can
     SSLs Be Used as Limits for  Urban Gardening?

     EPA's S SLs were developed to determine if the soil at Superfund (program that allows
     EPA to clean up hazardous waste sites) sites warrants further study, investigation or
     possibly cleanup depending on how a site is being used (for example, for residential
     or commercial purposes). These screening levels look at several soil-to-human
     exposure pathways, including: direct ingestion, dermal exposure, and inhalation.
     EPA's general guidance states that if an SSL is  not exceeded for a pathway of
     concern, the user may eliminate that pathway from  further investigation. While EPA
     does not have SSLs for gardening, some states may decide that residential SSLs are
     appropriate to use for gardening purposes, or they  may establish appropriate levels
     specific to each site.

soil amendments, plants, contaminants and their health

                               Wise  Urban  Gardening
                               In general, the benefits of urban gardening greatly outweigh the risks. By following
                               the recommendations and best practices  listed below,  you will decrease your
                               likelihood of exposure to contaminants that are commonly found in urban soils
                               located on sites with past industrial and commercial uses.

                               Q:     What Can I  Do to Lower the  Chances of Coming into Contact with
                                     Contaminants that May Be in  Present in my Soil?
                               A:     If you find that  the soil in which you want to garden is contaminated,
                                     you may want to first consult with your state and local environmental
                                     agencies and  EPA's  Technical  Assistance  to  Brownfields  (TAB)
                                     program (see Technical  Assistance  in the  Resources section,  page
                                     10) to learn about how  to find  professional site cleanup specialists
                                     who can recommend  the  best  techniques for reducing  high levels
                                     of contaminants. The following techniques are  commonly  used to
                                     eliminate exposure to soil contaminants:

                                     •   Build raised beds.
                                     •   Use soil  amendments to stabilize contaminants in soil. Adding a
                                         thick layer of organic matter to your soil provides a physical barrier
                                         to contamination. Soil amendments  have also been  used to bind
                                         contaminants so that they are no longer mobile or bioavailable. Soil
                                         amendments improve the overall soil  quality for growing plants and
                                         are a good addition to any soil.
                                     •   Remove all contaminated soil and replace  it with clean soil. Make
                                         sure the  replacement soil is clean by asking the supplier  for proof
                                         that the soil that was tested to be contaminant-free.
                                     •   Use phytotechnologies, which  utilize plants to extract,  degrade,
                                         contain  or  immobilize  contaminants  in  soil.  However,  using
                                         phytotechnologies to clean up contaminants can take many years,
                                         is not effective for every contaminant, and generally requires special
                                         handling for the disposal of  plants used.  Information on specific
                                         contaminants that can  be remediated using phytotechnologies is
                                         available  at:
Urban Gardening
More information for the urban gardener on soil science,
effects, and additional links is available on EPA's CLU-IN

      Build Raised Beds and  Container  Gardening

      Building raised beds and growing plants in containers is  the most common
      way to reduce the chances of coming into contact with contaminants in urban
      gardens. These gardening techniques are preferred because the clean soil and
      organic matter used to build the raised beds creates a physical barrier between the
      gardeners/plants and possible contamination in the ground soils. Raised beds can
      be built for permanent or seasonal use.

      How to build raised beds:

            •   Place a layer of landscape fabric on top of the ground soil before adding
               the clean soil and organic matter. The fabric layer creates a barrier
               beneath the soil in the bed that prevents plant roots from entering the
               ground soil below the bed.
            •   Build a frame to hold the clean soil for a permanent raised bed. Ask for
               non-treated lumber when getting wood to build the frame.

      See the National Gardening Association's how-to video on "Making a Raised Bed
      Garden," available at:

      Evenwhenyouareusing raisedbedandcontainergardensto address contamination,
      airborne contaminants,  soil dust,  or soil splashback from other areas may still
      enter the raised beds. Consider covering walkways and other areas of exposed
      soil with mulch, grass,  or other groundcover to help reduce  dust migration and
      splashback onto crops and protect against human exposure when gardening.

The    risks   associated   with
contaminant levels in soil  may
also be much lower than expected
based on test results because of the
bioavailability of the contaminant
in the  soil. Bioavailability  of  a
contaminant is the  amount of
contaminant that can be taken up
by your body.  It depends on the
characteristics of the site and the
soil. For example, for soils rich in
lead, treatment with phosphate and
compost has been shown to reduce
the bioavailability  of soil  lead,
decreasing the risk of exposure to
people  .

and Lead

Q: Lead is a common contaminant
in  urban  soils.   Can   I   use
phytoremediation to remove lead
from the soil at my site?

A: No. Phytoremediation of lead
in soils is ineffective since lead is
generally not available for plant
uptake. However, the use of soil
amendments is an effective way to
reduce potential exposure.
soil amendments, plants, contaminants and their health
                g 2011

                                                                                       COMMUNITY  6
                                                                                       ^    Open Dawn to  I
                                                                                           fd by Mister Girdmm f,
          Practices  in  the Garden
Building raised beds and mulching pathways is an excellent way to reduce the chance of coming into contact with potential
contaminants. The recommendations below can add another layer of protection if you have raised beds or decide to do in-
ground planting.

   •   Locate gardens away from old painted buildings and roads with heavy traffic.

   •   U S e a thick layer of organic material such as compost or mulch. Place landscape fabric between ground soil and
       new, clean soil.

   •   Watch over small children to stop them from eating soil through hand-to-mouth play.

   •   Wa S h hands immediately after gardening and before eating to avoid accidentally eating soil.

   •   We a r gloves as a barrier between your hands and the soil.

   •   Throw away the outer leaves of greens, especially from the bottom of plants, before washing. Soil particles
       are most likely to be located on the outer leaves of leafy plants.

   •   Wa S h produce using running water.

   •   Avoid bringing contaminated soil into the home by:
              •   Cleaning tools, gloves and shoes before bringing them indoors.
              •   Putting highly soiled clothes in a bag before bringing them indoors and washing them promptly in a
                 separate load.
              •   Washing off excess dirt from crops, especially root crops and leafy  vegetables, before bringing them

   •   Peel vegetables, especially root vegetables,  which are in direct contact with soil.
                                                       More information for the urban gardener on soil science,
                                                       effects, and additional links is available on EPA's CLU-IN

     Steps You Can Take to Reduce Potential Risk from Contaminants When Growing Vegetables:

     •   Add high rates of compost and other organic soil amendments to the soil (up to 50:50 by volume) in order to
         dilute soil contaminant concentrations, improve the physical properties of soil and plant growth, and make
         contaminants less available for plants to take up.
     •   Garden in raised beds or containers to separate the garden from the contaminated soil.

     To learn about safe levels of soil contamination and the cleanup requirements of sites used for gardening or
     farming in your area, contact your state environmental agency or cooperative extension services.

     Contact information is provided under Technical Assistance in the Resources section, page 10.
  Choosing  Crops
  In general, plants that produce fruiting bodies (for example, tomatoes, squash, apple and pear trees, and berries) are most
  appropriate for growing in potentially contaminated soil. Root and tuber crops (for example, carrots, potatoes and onions)
  are often the least appropriate plants to grow in potentially contaminated soil, as the edible portions of the crops are in
  direct contact with the soil. Vegetables with large outer leaves  (for example, cabbage, lettuce and collard greens) are easily
  contaminated by dust and soil splashback, so careful washing of these plants is necessary.

  There are many effective ways to reduce or eliminate any risk from gardening on potentially contaminated land. Gardening
  provides many benefits to communities and individuals. The information in this fact sheet is designed to help you understand
  the steps that your community can take to create healthy garden conditions for growing a variety of delicious and nutritious
  crops. So go dig, plant, harvest and enjoy!
soil amendments, plants, contaminants and their health

                                     Case Study
                                      LIBERTY LANDS
                                      Philadelphia, Pennsylvania

                                      Twenty years ago, the Northern Liberties neighborhood was the only
                                      zip code in Philadelphia without a community green space. Several
                                     tanneries contaminated the neighborhood. EPA conducted removal
                                    actions and cleaned up the site. Neighborhood residents worked with
                                   the City of Philadelphia to find resources for reusing the site. EPA
                                 provided soil testing and other technical assistance to ensure that the site
                               was safe for reuse as a park and community garden. Hundreds of hours of
                            donated time, monthly meetings, outreach and fundraising efforts resulted in
                       Liberty Lands community park becoming a reality. The park opened in 1996 and
     includes 37 garden plots and a composting area, an herb and butterfly garden, a children's playground, open
     space for community events, and community art and sculpture. The park is at the center of a revitalized
     community, surrounded by new residential and commercial redevelopment.

     For more information, visit
Resources for Urban  Gardeners

Technical  Assistance
 1.  Local  agricultural cooperative extension services can help with interpreting soil quality results (i.e., pH
     and nutrients testing) and provide a list of local environmental departments or laboratories that test for soil
     contaminants. U.S. Department of Agriculture extension services are listed online at:

 2.  EPA's Technical Assistance to Brownfields (TAB) program can help with questions regarding Phase I and
     Phase II Environmental Assessments. The TAB website is available at:
     In addition,  several TAB providers have experience working with communities to explore urban agricultural
     opportunities. These providers include:
        • Kansas State University:
        • Center for Creative Land Recycling (especially in California and Colorado):

 3.  State and tribal brownfields programs may be able to help with information specific to your state or tribe.
     To find your state brownfields program, visit: To find your tribal
     brownfields  program, visit:
Urban Gardening

Additional  Resources

General Information
More information about creating an urban garden is available at:

More information on soil science, soil amendments, plants, contaminants and their health effects, and additional links can
be found on EPA's CLU-IN website, available at:

Soil  Quality
More information on soil health is available at:
        EPA's Hazardous Waste Cleanup Information website:
        Cornell's Waste Management Institute website:
    •   Local agricultural cooperative extension services website:

The EPA Sector Notebook Series is a set of profiles containing information on specific industries. The notebooks can help
your community identify types of contaminants often associated with specific commercial and industrial land uses. The
notebooks are available at:

EPA's Toxics Release Inventory System provides useful information about the history of individual sites:

Information about the health effects of particular contaminants is available at:
        The Agency for Toxic Substances and Disease Registry (ATSDR):
        EPA's Integrated Risk Information System (IRIS):
        The Risk Assessment Information System:

In addition, EPA's Superfund Redevelopment Initiative website has a web page where reuse questions can be submitted:

Techniques for Addressing Soil Contamination
For more information on techniques for addressing soil contamination:
    •   EPA fact sheet: Soil Amendments for Remediation, Revitalization and Reuse Tools: Fact Sheet, available at:  www.
    •   EPA paper: The Use of Soil Amendments for Remediation, Revitalization and Reuse, available at:
        available at:
        EPA paper: Urban Agriculture and Soil Contamination: An Introduction to Urban Gardening, available at:
        available at:
        EPA fact sheet on brownfields redevelopment and local agriculture, available at:
        available at:
        EPA's fact sheet on phytotechnologies, available at:

Funding Opportunities
More information on funding sources for brownfields assessment, cleanup, revolving loans and environmental job training
is available at:

EPA's fact sheet on how to  apply for Brownfields Assessment Grants is available  at:
                                                                                            Spring 2011

.earning anout and taking steps to assess and address  potentia.
lontamination  can  help you to ensure that your urban garden area
         United States
         Environmental Protection

        Office of Superfund Remediation and Technology Innovation (5204P)
        1200 Pennsylvania Avenue, N.W.
        Washington, DC 20460
        EPA 542/F-10/011 I Spring 2011 I