The TRUTH about Treated Wood 👇 Some of the chemicals used in treated wood, particularly older formulations can be toxic to plants, while modern treatments are considered less toxic. Copper is an essential nutrient for plants which is used in most treatment processes, but as it leaches from the treated wood excessive levels can become toxic. Treated wood I would not recommend for the Veggie Garden: - CCA contains arsenic which is harmful to plants and humans. It’s being phased out and no longer