Question: We want to use treated pine in our landscape, both as landscaping timbers and as a retaining wall. Will the chemicals hurt our plants, our pets or us? We may have vegetables nearby. Also, what about using that lumber in an airtight greenhouse?

Answer: There should be no problem at all. Forestry experts tell us that the chemicals are bound into the wood. There should be no harmful seepage or volatile vapors. Railroad ties, by comparison, can be more of a problem, especially if they’re leaking the black creosote. It’s toxic to plants and probably shouldn’t be used next to vegetables or in the greenhouse.