We live on the edge of the NSW tablelands and have just built our
raised beds. According to the size of the beds you want - and if you
use the "no dig" method with hardly any soil, then you don't need 75mm
thick timber. We built boxes which are 3.6m by 1.2m by 300mm high,
using tallow wood planks 150mm by 25mm, screwed to battens and lined
with balck plastic on the inside. More than strong enough - and
termites don't like tallow wood. The other trick is to find some black
ant nests and transfer them close to your vegie beds. They won't harm
your vegies and they are reputed to destroy termites - neat biological
control.

If you really need to coat them with anything - there is now the new,
approved and environmentally safe version of the old Creosote,
available from Diggers of WA - but it costs three times as much.

Regards
Thedoc

Pat wrote:
I want to build some raised veggie beds, and refer to avoid treated pine. I
thought redgum "sleepers" might be good (not actual sleepers, but the planks
about 200mm high by 75mm), but I am a bit concerned about them succumbing to
termites. Is there any non-toxic preparation I can treat them with before
putting the soil in?