Up until 2003 the most common preservative used for pressure treated wood was chromated copper arsenate cca a compound using arsenic.
Pressure treated wood for raised beds safe.
If you do use any pressure treated lumber you would want to use thick plastic or some other barrier between the soil and the wood to be on the safe side.
Lamiot wikimedia commons pressured treated.
Yes the new pressure treated wood is safe for use for raised garden frames.
Treated lumber many new gardeners and even experienced ones turn to treated lumber when sourcing materials for raised beds due to its added protection against moisture and the associated rot and bug damage.
If you have concerns about using acq treated wood for raised beds paint or stain the wood use a heavy plastic liner between the wood and your soil or use a non wood building material e g stones bricks.
Is it safe.
Here s what i know.
Joe mabel wikimedia commons there is a long standing controversy in the field of organic gardening.
However while treated lumber will hold up better over time it can also leach harmful chemicals into your soil.
He stated in a bulletin titled treated wood in raised bed gardening scientific evidence and data have shown that using pressure treated wood for raised bed or box gardening is safe to adults and children in terms of the plants grown and used in these containers.
Wood treated with chromated copper arsenate or cca can leach toxic arsenic into soil.
Avoid using older types of wood treatments such as cca creosote and penta treated lumber.
The safety of pressure treated wood for garden beds depends on what preservative was used to treat the wood.
The safety of pressure treated lumber for raised bed gardens has been examined by several researchers.
Concerns have focused on the leaching of arsenic from pressure treated wood into the soil contaminating plants and people.
From what i ve seen the consensus is that the chemicals do leach out of the wood into the soil and are uptaken by the plants in very small amounts.
Can pressure treated wood be used as part of an organic vegetable garden.
See additional resources below.
Wood that isn t pressure treated tends to rot fairly quickly in contact with the soil.
With a few precautions.
A barrier would not only prevent the dirt from making contact with the lumber but also help extend the life of the lumber by reducing the water exposure.