Lumber for raised vegetable beds
Hello! I am building raised garden beds, I'm using untreated cedar for the boxes. Is it ok to use pressure treated posts at the corners of the beds ( to stabilize the boxes)? The posts are to be dug in by about 4 inches. Thank you! Chris oliver
Washington County Oregon
Cedar is a good choice for raised vegetable beds.
For the corner posts, Oregon State University has done research on the new type of pressure treated lumber and found it is safe for use for vegetable gardening. The original pressure treated lumber used arsenic as one of the components for pressure treating. The new (since 2004) pressure treatment Alkaline Copper Quaternary (ACQ) is safe for use in raised beds. Here is the link to an OSU paper on using ACQ pressure treated lumber in raised beds. http://extension.oregonstate.edu/question-of-the-week/raised-bed-lumber-pressure-treated-safe.
If you still have concerns, 4"x4" cedar or juniper posts will last for many years too and are not treated wood products.
Please let me know if you have any further questions.