Growing food in urban soils can be a challenge, and it is important that all food grown in GreenThumb gardens is done so in the safest manner possible. To help educate and support GreenThumb gardeners in growing food in the safest way, we have summarized GreenThumb’s requirements and best practices here, and in more detail, in the attached document. Please take a look and contact your Outreach Coordinator if you have further questions.
Prevent heavy metals from entering your food by adhering to the GreenThumb requirement of growing food crops in containers or raised beds lined with landscaping fabric and filled with clean topsoil and compost. In addition, we recommend the following guidelines:
- Add organic matter such as compost to your soil. Organic particles will bind with metals and help prevent them from being absorbed by your plants.
- Keep pH levels close to neutral and make sure drainage is adequate helps to assure that the contaminants don't move in your soil. Your ideal pH level is between 6.5 and 6.8. If soils contain heavy metals, a pH closer to 7.0 is better.
- Keep play/seating areas and pathways covered in mulch to reduce exposure to the soil.
- Wear gloves when gardening and thoroughly wash hands after gardening. Shake off any excess soil from boots and clothes before going home.
- Thoroughly wash produce and peel root vegetables before eating.
For free lumber, soil, compost, wood chips, and mulch, pick up request forms at any GreenThumb workshop!
- Download GreenThumb Safe Soil Gardening Requirements (PDF, 227 KB)