Weatherproofing the boxes?

I originally planned on using wood stain to protect my boxes but am now wondering if teak oil might be a better choice. Does anyone have any experience using the teak oil?

My first two boxes are cedar and may not really need treating but I am thinking the situation over carefully. My biggest worry is runoff pollution from the coating material. It probably would not be big but any is more than I want in my organic garden. Linseed oil is a possibility but even some of it has undesirable things in it from the mfg. process, tung oil is supposed to be food grade and is used for wooden bowls etc. again some of that can be tainted. Most products that can be food safe also have versions that are not food safe and all of them seem to wear off in water so would need regular replenishing. I have not done it yet but going to some quality paint stores such as possibly Sherwin Williams could put you in contact with a product savvy expert and then some of them don't know squat in spite of their attempt to tell you what to do. I have had no luck Googling the issue. Locally The Woodsmith Store is where I have most faith in the sales staffs knowledge 1-800-444-9494. They are owned by a large woodworking publisher August Home and do strive for excellence. I talk to Dave, Dave, Gary, Gary, John or Tom regularly with confidence, they are always no pressure and eagerly obliging that is company policy. They could lead you to a particular manufacture for more info too. When I have time that is on my todo list but for now unfortunately is on the back burner.