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Safety in the Garden

Gardening is fun and can be a great way to get students interested in learning! But first consider these safety issues.

Before you begin your school garden program, you will need to ensure that the soil, water, and working environment are safe for the students. Test the soil for contaminants, know what is in soil amendments, the water and plants, and develop rules for working in the garden. Talk with the students about these important issues, and let them help develop the rules to be used in the garden.

Soil Preparation


Do not use fresh or unsterilized manure. All animal manure is potentially hazardous and may contain E. coli as well as other disease-causing pathogens. Use only sterilized or fully composted manure. Aged manure is not the same as composted, and can contain disease-causing organisms. For more information, contact your local county health department or cooperative extension office.

Lead Contamination

Lead is naturally present in all soils, generally in low levels, but pollution can increase lead to harmful levels. If you plan to plant an edible garden in an area that may have lead-contaminated soil, first test a soil sample for lead to determine if the soil is safe.

This is a critical issue for schools. Areas at risk for lead contamination include those with a history of construction before 1978, where lead may have leached into the soil from paint or other materials, or a history of heavy exposure to traffic that at one time used fuel-containing lead. However, to be on the safe side, it is always a good idea to test the soil for lead before beginning an edible garden project.

For general information about lead contamination, visit Cornell University’s Web site External link opens in new window or tab. . For information about lead testing, contact your local county health department or cooperative extension office.

Underground Pipes

Prior to developing the garden space, check with the school district or local utilities to determine if there are any underground pipes or cables that may be a potential problem. If digging begins without getting an “all clear,” the chance exists of running into electrical cables, water pipes, or a gas main.


Make sure all water used in the garden – for watering plants, washing produce, and washing hands – is potable (drinkable) water. In addition, water for washing hands and produce should be running water to prevent recontamination.

Some newly developed school grounds may have two separate water systems – one for potable water and one for recycled water (used for irrigation). Check with district administrators to determine if this is an issue at the school site. Then make sure only potable water is used in the school garden. For more information on recycled water, contact the WateReuse Association External link opens in new window or tab. .

Building Materials

Do not use railroad ties, treated lumber, or old tires for garden boundaries, raised beds or anywhere in the garden. These items contain toxic chemicals that can leach into the soil and be absorbed by the plants. Old railroad ties contain creosote, a carcinogen; treated lumber contains cyanide, a potent poison; and tires can leach petroleum products into the soil. Contact your county cooperative extension office for more information.

Harmful Plants

Some plants and plant parts are poisonous. Others, such as poison ivy or stinging nettle, can irritate the skin. Teach children never to taste a plant unless an expert says it is all right to eat. Refer to the List of Hazardous Plants below for more information or contact the local poison control center.

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List of Hazardous Plants

Hay Fever Plants
Dermatitis & Skin Rashes
Plants That Harm When Eaten

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Questions:   Education and Nutrition Policy Unit | 800-952-5609
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