I want to build some cold frames but am confused about what type of wood to use.
Treated or untreated wood for garden box.
This type of treated wood was banned years ago for household use.
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.
A cedar frame can last up to 10 years but one made of douglas fir may last only 5 to 7 years.
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.
The wood gets a lovely rustic barn board patina after just one season.
A redwood raised garden bed however can last up to 20 years.
The wood that people worry about leaching chemicals into the soil is cca chromated copper arsenate pressure treated wood or old railway ties.
I am concerned about using pressure treated wood around my veggies because of the arsenic.
Stephen in huntingdon valley pais the new pressure treated nature wood safe to use as a framing material for a raised bed vegetable garden.
But i fear attracting termites with untreated wood.
Compared to untreated wood pressure treated lumber lasts longer and is available at a comparable cost.
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.
Creosote treated wood is not a good option for vegetable raised beds.
I also use some pressure treated wood for various garden structures including large raised beds.