Composite wood frame safety for vegetable gardens - Ask Extension
Hello! Can you tell me if it is safe to grow vegetables organically in a raised bed box made out of composite wood.
Knowledgebase
Composite wood frame safety for vegetable gardens #896833
Asked April 09, 2025, 3:15 PM EDT
Hello! Can you tell me if it is safe to grow vegetables organically in a raised bed box made out of composite wood.
Polk County Oregon
Expert Response
Dear Gardener,
Thank you for contacting us about using composite wood to construct raised vegetable beds.
The use of composite lumber for raised beds has not been researched. According to the University of Vermont Extension, composite lumber is made from a combination of wood or pulp fibers mixed with plastic resins. The amount of each component varies by manufacturer and may determine longevity of the product, and manufacturers do not recommend letting it come into contact with soil. Chemicals are added to composites to prevent decay, and these may leach into the soil. The actual and environmental costs of composites is higher than cedar or pine and have about the same life expectancy.
The current formulations for pressure-treated wood are considered safe for food production. However, USDA Organic Certification guidelines do not allow for pressure-treated wood to come in contact with plants grown for food.
Lumber products of cedar, redwood, or hemlock are good choices due to their natural resistance to rot and decay.
I hope this is helpful. Please write again if you have any questions.
Thank you for contacting us about using composite wood to construct raised vegetable beds.
The use of composite lumber for raised beds has not been researched. According to the University of Vermont Extension, composite lumber is made from a combination of wood or pulp fibers mixed with plastic resins. The amount of each component varies by manufacturer and may determine longevity of the product, and manufacturers do not recommend letting it come into contact with soil. Chemicals are added to composites to prevent decay, and these may leach into the soil. The actual and environmental costs of composites is higher than cedar or pine and have about the same life expectancy.
The current formulations for pressure-treated wood are considered safe for food production. However, USDA Organic Certification guidelines do not allow for pressure-treated wood to come in contact with plants grown for food.
Lumber products of cedar, redwood, or hemlock are good choices due to their natural resistance to rot and decay.
I hope this is helpful. Please write again if you have any questions.
