Can treated wood be used for fence posts, trellis systems, etc. in organic production?
As provided in the National Organic Program (NOP section 205.206(f)), producers must not use lumber treated with arsenate or other prohibited materials for new installations or replacement purposes in contact with soil or livestock.
The Preamble (Crop Production--Changes Based on Comments (7)) elaborates on 205.206(f) as follows:
“This provision prohibits the use of lumber treated with arsenate or other prohibited materials for new installations or replacement purposes in contact with an organic production site. We included this modification to clarify that the prohibition applies to lumber used in direct contact with organically produced and handled crops and livestock and does not include uses, such as lumber for fence posts or building materials, that are isolated from production. The prohibition applies to lumber used in crop production, such as the frames of a planting bed, and for raising livestock, such as the boards used to build a farrowing house.”
Lumber used in organic crop production, such as for tomato stakes or grape trellis, and lumber used for raising livestock (such as the boards used for a chicken roost) which have direct contact with crops or animals, must not be treated with prohibited substances. The prohibition does not include other uses, such as lumber for fence posts or building materials, if the treated lumber is isolated from organic animals or certified land. Before using any treated lumber, check with your certifying agent.