We’re planning to build a raised garden bed this spring. Can you recommend materials we could use that won't leach chemicals into the soil (and our veggies) and still be durable?
Congratulations on tackling such a worthy project. Who wouldn’t want their own local and organic produce within reach? Other benefits of raised garden beds are preventing soil compaction, as well as good drainage and a barrier to pests like slugs and snails. Within each bed, you can also tailor the soil type depending on what you plan to grow – sandy soil for strawberries, for example.
The best choice is natural cedar. It’s rot- and insect-resistant and is low maintenance. There’s no need to treat it. And you’re right, to avoid toxins leaching into your garden vegetables, you should avoid reusing anything like creosote-treated railroad ties or treated lumber. By treated lumber, I’m referring to lumber with chromate copper arsenate, or CCA. While you won’t find CCA-treated lumber in your local hardware store, suppliers still make it available to contractors. Some cities have even banned its use in playground construction.
Other options are stones, bricks or, more recently on the market, plastic lumber. Plastic lumber worth considering is the type made from 100 per cent recycled material, often high-density polyethylene (HDPE) or your old plastic #2 milk jugs. Now, I haven’t seen any research about leaching for this material, but HDPE is known as one of the safer types of plastic and it’s a way to embrace reusability.
Lindsay Coulter gives you the straight goods on living green. Send your questions to firstname.lastname@example.org. For more great tips, visit The David Suzuki Foundation at davidsuzuki.org.