Easily earned with no effort in the tutorial world.
Head across the bridge to the castle. Go in the entrance on the left side, and up the stairs immediately to your right. You will find a table covered in pots. Just punch one, pick it up, and place it back down anywhere. Achievement Unlocked!
EDIT: Looking at the comments, this does seem to be a little buggy. If the above trick doesn't work for you, then you'll have to make one yourself. You'll need 3 clay balls. Clay can be found in shallow areas of water. Then cook the clay balls in a furnace to make bricks. Then just craft the flower pot on a crafting bench and place it down.