I'm considering building raised garden beds on a sloped area of my property, which has a history of being near old orchards. I'm testings the soil for lead and arsenic since the trees might have been exposed to pesticides long ago. Regardless of the results, I plan to build eight 4x12 raised beds for easy access and minimal bending. I'm leaning towards using dry-stacked stone for the walls since it's fairly affordable, but I'm wondering if there are any significant reasons to choose wood instead. Also, what materials can I use underneath to contain the soil that won't allow plants to grow through and won't decompose over time?
2 Answers
I've had wooden raised beds for a few years now and they're holding up fine, but I do plan to switch to stone eventually because the wood is starting to show some minor wear. If you have a good source for inexpensive stone, it might be a wise long-term investment, as stone beds typically last a lot longer than wood does—usually around 6-10 years before decay starts. Plus, you get that added sturdiness with stone!
Pesticides really tend to wash out with rainfall, so the lead test you’re doing should give you a clear picture. If you’re leaning towards using stone, just keep in mind that wood is often cheaper. However, if stone isn’t going to break the bank for you, then it's the more durable choice for beds. Just consider laying a weed barrier and some gravel underneath to help retain the structure; keep in mind you'll need to replace that barrier every few years.
I’d heard that lead doesn’t wash away easily, though. I'm really curious to see what my test reveals.