I have a convertible hand truck. But it is not from Harbor Freight, and like I said, it is straight-backed. I have used it with bungee cords to hold on to large potted plants but it is not ideal. I have lost a few along the way, breaking precious plumeria branches, tearing off palm frond. Not a pretty sight! I doubt my Harbor Freight will have the one with the rounded back. I will have to search different stores to find the one I want since it is only available in stores. There is one by Northern Tools for $100 more. AND they want $100 s/h! Nope!!
Anyway, the convertible hand truck is indeed handy. It has air-filled tires and rides easily over any surface. I have never had any issues with it going over anything I have pulled it over. But just to make it easier on myself when moving plants, I set up ramps over the steps and used 2 pieces of plywood on the lawn. BTW Harbor Freight Convertible Hand Trucks are on sale right now for $49.99 through the end of the month. They really are handy to have. If only it had a rounded back for pots! Shucks!
