It’s spring, and everyone is out in the garden. This question came in this week:
“What type of material do you use for constructing raised beds? We’vedone some raised beds in redwood, but we are concerned that they willrot. What is a safe and long lasting sealer to use for wood raisedbeds? or are there other economical composite materials to use inconstructing beds? Thanks, Yasi”
Great question, Yasi. I’ve built raised beds out of many different materials, including Douglas Fir (which everyone says only lasts a few years, but mine are 10 years old and still going strong), redwood, cedar and Trex Decking. These materials last the longest in the order I listed them above.
You can expect about 10-15 years from your redwood beds if they are unlined and untreated. The finish I would recommend, if you want to coat your beds, is linseed oil. It’s a natural oil from the flax plant that is mixed with a resin that permeates and seals the wood nicely. It’s non-toxic and will protect your wood from rotting before its time.
I’ve used this linseed oil to finish a cabinet that I built with my father years ago. It takes several coats, but any level of application will help extend the life of your wooden raised beds:
As far as economical composite materials for raised beds, the only one I have used is Trex Decking. It isn’t exactly economical up-front (it’s about a third more than lumber), but it will last for 50 years, so I feel that it’s worth the extra expense. You have to order it from the contractor’s desk at Home Depot, because the stuff they stock on the shelves is not safe for soil contact. Trex is. There is a product called Nexwood, but I haven’t worked with it yet. Nexwood is hallow on the inside, whereas Trex is a solid product. Trex cuts and drills like wood. You can see our raised beds that we built a few years ago:
You can check out the whole process by searching for Raised Beds on the home page.
I hope this helps. Thanks for writing in.
Hey – if anyone out there has an experience that you’d like to share about building your raised beds, share it with us here!