I received this question from one of my students from Seattle Farm School. It is a great one that no one has asked me before!
Untreated wood is recommended for vegetables beds as it will not leach chemicals into the soil. Many people fear that arsenic will leach into garden beds if you use treated wood…but arsenic hasn’t been used since 2003 in pressure treated wood! The process that gave treated wood a super bad reputation CCA (chromated copper arsenate) was replaced with a new process called Micronized Copper Quaternary (MCQ). Click HERE for a good read on treated lumber and garden beds by The Survivalist Blog. Now I am not saying treated wood is as safe as untreated…the decision of what type of wood to use is up to you.
Now facts….untreated wood will decompose quicker and need to be replaced sooner. Which is what led to question I received…how can you extend the life of a untreated bed, are there safe stains out there? Yes, there are! We actually just used one on our cedar fencing called Penofin Verde. We also used cedar since it is naturally water resistant. Redwood is another good option. Although both options are on the pricey side. Penofin Verde is just one of many stains that could be used on a garden bed. Gardenista has a nice blog post on 5 other stains recommended for raised garden beds HERE.
While my fence was made with untreated lumber and stained with an eco-friendly stain my garden beds were not. I know some of you may be gasping! We made the choice to use treated wood so they would last a long time, our beds are two feet high and on top of that they are located where the yard is 6 feet higher than the street level. In other words it was a major pain to get them in place & filled…we don’t want to ever do it again! 🙂 I did line my beds with plastic though to reduce the chances of any type of leaching.
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