Which timber for raised veggie patch?

[renosouth1234]

I want to make a raised veggie patch with sleepers and every post I see says to use sienna sleepers because they’re food safe. It seems they are no longer available or at least in my location. What is the other alternative? I will be putting landscaping fabric along the inside.

[MitchellMc]

Hi @renosouth1234,

You might like to read through this guide on How to choose sleepers for your garden bed. Also, here's a helpful guide for the construction: How to build a raised garden bed and How to fill a raised garden bed.

You don’t need Sienna specifically, so don’t worry too much about not being able to find them. Sienna was simply a brand name for a reddish toned sleeper that used a non-CCA treatment, and over time people started using the name as a kind of shorthand for “safe for veggie gardens”.

What really matters is the treatment type. You just want to avoid CCA-treated sleepers because CCA uses an arsenic-based preservative. CCA is being phased out for domestic use, and most treated pine sleepers you’ll find now are ACQ or similar copper-based treatments instead. ACQ, hardwood sleepers, and treatments like MicroPro and Tanalith E all fall into the safer category for use around food gardens because they do not contain arsenic.

If you want complete peace of mind, you can still line the inside of the bed with a heavy-duty builder’s plastic so there is no direct soil to timber contact. You can also look at concrete or composite sleepers if you want to avoid preservatives altogether, but for most people, an ACQ or MicroPro-treated sleeper is perfectly suitable for a veggie patch.

Please let me know if you have any questions.

Mitchell