All our vegetable patches are raised garden beds, meaning we do not dig into the ground, but build on top of it. The beds are 20cm - 40cm high and encased in natural timber. We use untreated macrocarpa timber for all our raised beds. Treated or tanalised timber contains harmful chemicals such as copper, chromium and arsenic (CCA) which are injected into soft wood to prevent fungal disease and termites. CCA leaches from the timber through weather and rain.