Treated Or Untreated Wood For Garden Box

Current treatments such as alkaline copper quaternary acq are deemed low risk by the epa and designated safe for use around humans pets plants and vegetables.

Treated or untreated wood for garden box.

I also use some pressure treated wood for various garden structures including large raised beds. Creosote treated wood is not a good option for vegetable raised beds. The wood gets a lovely rustic barn board patina after just one season. Top your bed with boards of untreated lumber to make a flat top to sit on and to avoid contact with the wood particularly if you have cca treated wood in your garden.

Untreated wood deteriorates more quickly in contact with soil and will have to be replaced possibly every two to five years though heat treated wood may last a bit longer. The wood that people worry about leaching chemicals into the soil is cca chromated copper arsenate pressure treated wood or old railway ties. The durability of untreated wood used for raised beds largely depends on the type of wood used. A cedar frame can last up to 10 years but one made of douglas fir may last only 5 to 7 years.

This type of treated wood was banned years ago for household use. You can isolate pressure treated wood by lining the inside of a bed with heavy plastic to prevent leaching of chemicals from the wood into the soil. Redwood and cedar are more rot resistant and last longer but are also more expensive. I am concerned about using pressure treated wood around my veggies because of the arsenic.

A redwood raised garden bed however can last up to 20 years. But i fear attracting termites with untreated wood.