If you are planning on building a raised bed to grow your veggies in then you will want to know that the wood is safe to use.
You will want to use pressure treated (sometimes referred to as tanalised) wood for your beds.
This is so that they will last much longer than normal wood, which could rot after just a few years. But is pressure-treated wood safe to use for vegetable gardens? Let’s have a look and find out.
Can you use pressure-treated wood for Vegetable Gardens?
Yes, you can. Modern pressure-treated wood is fine to use for growing food.
So, why the confusion?
Well, as it turns out, there is still some outdated information online telling you not to use pressure-treated wood for raised beds, so what gives?
Well, the advice was sound at the time and still is concerning old-treated wood. What has changed is the wood treatment itself.
It used to contain arsenic, but this treatment was banned in the EU and is still banned in the UK after leaving the EU.
A lot of confusion is also brought about by this treatment not being banned in the USA, and that pressure-treated wood may not be safe to use for your veggies in the USA and other parts of the world.
A lot of gardening info is shared between the USA and the UK so you may find yourself on an American blog which tells you not to use pressure-treated wood. Even though our pressure-treated wood is very different to theirs.
I am no expert on that, and this guide is only about pressure-treated wood in the UK and EU, which is safe to use!
It used to be that all pressure-treated timber had lots of pretty nasty stuff in it. Stuff like arsenic and high levels of chromium.
This has all changed now and the pressure-treating process now uses a copper-based treatment. The older process of using arsenic has been outright banned so you don’t have to worry about buying wood that has been treated in that way by accident.
You can no longer use copper, chromium, arsenic (CCA) preservatives to treat timber in the UK. All wood preserving products containing arsenic and chromium were banned from sale from 1 September 2006.
What this means is that any new pressure-treated wood is safe to use for raised beds but won’t last as long as old-treated wood used to. The new treatment, while safer, doesn’t provide as much protection.
Using Pressure-Treated Wood
I garden organically at my allotment, and I feel very safe using pressure-treated wood for my raised bed builds. In fact, I have used decking boards and gravel boards to build raised beds.
Can You Use Pressure Treated Wood For A Compost Heap?
Yes, you can. Just as it is safe to use for vegetable beds, pressure-treated wood is also fine to use for building a compost heap.
Because of the pressure treatment, it will also rot slower, meaning you will be able to get plenty of years of use out of your compost heap.
What About Railway Sleepers?
Reclaimed railway sleepers are not safe for growing food crops in. This is because they are treated with all sorts of products over their time, often including the aforementioned CCA treatment and tar and who knows what else.
New softwood railways sleepers sold directly to the consumer are safe as these are pressure treated using the new methods.
Oak sleepers are even better as these are often not treated at all as the oak is strong enough to last – but you will pay a premium for these.
If you want to learn more about pressure-treated wood in gardening, then there is an interesting paper from Penn State University all about its uses and dangers.
One interesting snippet is they found that even the old style of treatment carries little risk.
Although the plant and human health risks from garden uses of CCA-treated lumber appear to be extremely small, there are steps gardeners can take to further reduce any such risks.