Maybe something like this?:
A simpler solution. No need to solder.
You'll have to learn to solder. Use the best bucket for the body. Cut one of the other buckets into a spout. Cut a hole in the side of the body and solder the spout in. Cut one of the buckets and form a handle. Solder it to the opposite side of the body. put the lid on the body and cut a hole on the handle side to use for a filling hole. Get a small tin can and form the opening to fit the end of the spout. Solder it on the spout and use a nail to punch holes in the bottom of the tin can for the water to come out in a gentle rain like stream. Paint it a nice spring color and you now have a nice homemade watering can.
Or if you don't want to learn to solder, JB Weld would also work. Soldering would be prettier, though.