Although there are other ethical questions regarding the use of Redwood (deforestation, and erosion to name only two), I prefer Redwood timbers for raised vegetable and herb beds such as those shown above. If not Redwood, then another non-toxic wood option such as Cedar (which grows more quickly, but is not available in larger timbers) or masonry, if the budget allows. Straw bales also make great raised beds, albeit less permanent than outdoor wood options.

Thanks for the great question! And keep up the good work keeping toxic chemicals out of your environment! The less we support the chemical market, the sooner it will disappear.