Among homeowners, there has been some debate over using pressure-treated lumber when building raised beds for the home vegetable garden, specifically regarding the safety of our food consumption. As a mother, I completely understand the concern. I’m an organic gardener because I want the best for my family–no toxic chemicals, pesticides, GMOs, etc. While my main garden is in-ground, I also have a raised bed.
After some research, I decided to construct my bed using pressure-treated lumber. Why? Primarily cost. Compared to cedar, it’s almost a 1/3 of the cost. Next, availability. I can buy pressure-treated wood from any local hardware store.
Modern Pressure Treated Wood
According to Wood–It’s Real, pressure treated lumber (southern yellow pine) is a great choice and will ensure your project lasts for many years to come. Best of all, it’s safe for growing food.
“Much of the concern about pressure treated lumber comes from a fear of adding arsenic to the soil. While arsenic is indeed dangerous, it hasn’t been used to treat residential lumber in over a decade. Since 2004, the EPA ended use of arsenic in residential applications, so today’s lumber is treated with copper to prevent decay. Copper is a mineral that your body actually needs trace amounts of, and it’s much less dangerous than arsenic. If you buy new pressure treated SYP for your raised bed project, you can feel good about using it for garden projects where you plan to grow food.”
Ingredients found in pressure-treated lumber like Cr and Cu, are unlikely to harm, because they are bound very strongly by soil particles, especially by soil clays and organic matter. Besides, the human body can tolerate relatively large intakes of Cr and Cu and is also able to excrete excess amounts of these metals. Furthermore, plants are less tolerant of Cr and Cu than humans are (if it made it into the plant tissue in the first place). This means that Cr and Cu would kill plants before plant tissue concentrations could get high enough to cause a chronic toxic effect in humans from eating the plants!
Why Copper Is a Good Choice
“Copper as an element binds strongly to soil, particularly to soils with a neutral pH of 6 to 7 and highly fertile soils. This means that the copper will stay put and is unlikely to be absorbed into plants you intend to eat. You probably won’t even have to think much about this, as vegetables grow best in neutral soil anyway. Keep fertility up by adding plenty of compost, and you’ll make your plants happy while keeping copper absorption to a minimum.”
Copper is also an organic-approved fungicide for use on your fruit and vegetable plants.
Organic Materials Review Institute
However, if you’re interested in purity, the OMRI guidelines do not allow for anything other than untreated wood, leaving cedar as your best option.
Still concerned? Line your raised beds with plastic. This will create an impermeable barrier between your plants’ roots and the pressure-treated lumber that edges your beds.
Maybe it’s me or my equipment, but I find the light-grey font color against the white background difficult to read. Otherwise, these are very attractive pages, and informative. Thanks!
Totally understand. Thank you for taking the time to visit my blog!
You should absolutely not used pressure treated wood in a vegatable garden this is terrible advice
Love the strong claim with no evidence! Very helpful, thank you!