My contractor used wide poplar floorboards in the restoration of my antique cape -- in several rooms where the original floors couldn't be saved. To stain it, you must, after sanding, etc., WASH THE FLOOR WITH A LYE MIXTURE (about 6 - 8 ounces of lye per two quarts of water, let sit overnight before using). Use eye/hand protection. This will etch the wood to take stain better, which you may apply after the lye/water dries. You will still need two coats of stain. If you already have stained once without this prep work, you could try staining again...if that fails, paint instead.