A: possibly. you must drill holes for water drainage. otherwise the water will freeze and expand during the winter and crack the planter. also cover the top of the planter with plastic, tarp etc to prevent water from entering.
A: The top measures 23.5 inches and the bottom measures approximately 13 inches in width.
A: They are not cheap shiny plastic if that is your concern (am not certain exactly what resin is technically, but these don't look like cheap plastic pots). However, I find the ones I have had for about 2 years are not holding up as well as I had hoped (they fade). Also, I believe they are only single walled, while those of another manufacturer I have switched to are double walled.
A: The planter is 21" wide at the bottom.