Have been building raised garden beds and have been racking my brain to find a way to preserve the timbers used to raise the beds from termites, of coarse you wont there to be no chemicals and non expensive as money is an issue. Where the timbers sit on the ground will become moist and eventually start to rot which is what termites love to eat. After thinking about this for a few days I thought to myself ,you dont see termites eating into burnt wood as charcoal doesn't rot and is no-longer in a form that termites will eat. I got a gas bottle and a my propane torch fitting which is 50mm wide ,the same width of the timber and slowly went along the timber burning it as I went. Hosed it down with water once finished ,job done and at almost no expense. I will be doing this to any wood that goes into the ground from now on.