Geelong loves a good veggie bed and a common question we get asked is whether or not it’s safe to use Treated Pine. This is because there has been a lot of discussion around the safety of standard Treated Pine (CCA Treated Pine) due to the use of arsenic in the treatment process.
What the researchers say
There are a few schools of thought on the safety of Treated Pine. The Timber Preservers Association of Australia advise that CCA Treated Pine isn’t a concern in a gardening context. Their research has shown that preservatives like CCA are not absorbed into grapes, tomatoes and cucumbers but they do admit some root crops like carrots and beets have been reported to pick up small amounts of arsenic. However this trace amount is said to be an organic, non-toxic form and in any case is largely removed by peeling the vegetable.
The CSIRO say the potential ingestion of arsenic from CCA treated timber is within tolerable limits. Therefore they believe the timber can be used around veggie gardens if you take some precautions.
What we advise
As you can see, while the risks seem to be low, there is conflicting information out there and some calls for caution. So if you are concerned about risks, we recommend taking a couple of simple precautions as you build your veggie bed so that you can have peace of mind when eating your home-grown veggies.
1. Paint the Treated Pine
You probably want to paint the outside of the bed to match your home so take a little bit of additional time to paint the inside of the bed as well. Use an exterior grade paint as that will help prevent the Treated Pine from making direct contact with the soil.
2. Line the bed with builder’s plastic
Another way to protect the soil from making contact with the treated pine is to line the bed with builder’s plastic. A thick waterproof plastic lining is a surefire way to isolate the treated pine from the soil and can be done as the only precaution or in addition to painting if you’re super concerned.
Why does pine need to be treated at all?
Pine is a durable building material and is popular because it’s generally more cost effective than other timbers. This is largely because it’s relatively fast growing and through managed plantations, can be a sustainable alternative to old growth timbers.
However being a softwood, it is very susceptible to water damage if un-treated. In fact it’s strongly recommended that you never use un-treated Pine in outdoor situations as it usually has a very limited lifespan.
This is where treatment comes in handy because it gives Pine qualities that are usually only available with hardier timbers like redwood, but at a fraction of the cost.
Leen’s Building Supplies believe’s that the above precautions will suffice however there are plenty of alternatives if you’re still not sure. Here’s a quick round-up.
ACQ Treated Pine
ACQ Treated Pine is a great alternative that is arsenic-free. It looks the same as CCA Treated Pine, and will last just as long.
Ecowood is another arsenic-free Treated Pine that uses a different treatment method from ACQ. Again it is non-corrosive and will last the test of time.
Untreated Hardwood & Colorbond
Of course, there are many alternatives outside of pine to consider! Hardwoods make beautiful edging and untreated hardwood has a strong durability rating. Colorbond and galvanised sheet metal is also a great option that can match your roof!
If you have any questions about your Geelong veggie bed project and timber types please get in contact with us via our enquiry form or give our friendly team a call on 5278 9464.