I watched a TV show last night where a family was building an off-the-grid greenhouse. Part of the greenhouse was built into the side of a hill so that the greenhouse can remain unfrozen during the harsh winters of northern Washington state. While the idea is terrific, the toxic materials they used made me cringe.
The back and two sides of the structure that are dug into the hill was supported by used railroad ties treated with creosote, a carcinogenic (cancer causing) chemical used to preserve wood. I held out hope that once the inside of the greenhouse was finished, they would install raised or elevated beds, but nope, they looked to be planting right into the ground where the plants they are growing can be exposed to the leached chemical in the ground. It did, however, look like they may have painted the railroad ties to help alleviate the creosote leaching into the ground.
If you are going to make raised beds or greenhouses, please do NOT use railroad ties, even if you are going to line your boxes or paint the wood. Toxic chemicals have no place in a food plot. The health of your family should always be considered when choosing the material you use to make your planter boxes. Here at Aaron's Homestead Products, we make all of our planting boxes with untreated/natural cedar lumber, it is very long lasting and not toxic at all.