My planter boxes appear to be solid and well-constructed.  I stained then with Sikkens Cetol Natural, and they look absolutely beautiful.  I’m looking forward to seeing plants in them soon.  They arrived packaged in cardboard which looked like it had been sprayed with some kind of packing foam that hardens on contact.  The foam was highly effective in preventing shipping damage, but was an absolute nightmare to remove and discard.  I have no idea whether the foam-covered cardboard can be recycled.  The foam broke into little pieces which are electrically charged and clung to everything, especially me!  It is impossible to clean up.  My garage looked like a snowstorm after the unpacking session which took over three hours for five planters.