The big shelf type boards are poplar I believe and the side pieces are pine. We used screws to screw them in, guess i forgot to put that you needed an electric screwdriver. We're planning on using back heat for the baby corns I believe although I dont think they're be a problem if we decided to use belly heat. We might need to take a sander to the shelves to create a tiny bit more room but the flexwatt is pretty thin so I don't think it'll be an issue.