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.
Treated or untreated wood for garden box.
Creosote treated wood is not a good option for vegetable raised beds.
Compared to untreated wood pressure treated lumber lasts longer and is available at a comparable cost.
Redwood and cedar are more rot resistant and last longer but are also more expensive.
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.
The durability of untreated wood used for raised beds largely depends on the type of wood used.
The wood gets a lovely rustic barn board patina after just one season.
I want to build some cold frames but am confused about what type of wood to use.
A cedar frame can last up to 10 years but one made of douglas fir may last only 5 to 7 years.
I also use some pressure treated wood for various garden structures including large raised beds.
But i fear attracting termites with untreated wood.
Stephen in huntingdon valley pais the new pressure treated nature wood safe to use as a framing material for a raised bed vegetable garden.
This type of treated wood was banned years ago for household use.
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.