I made these planters the other day with my boys. What an easy project.
I already had some 1x6 wood and some 2x2's in my shop. I cut the boards to 14 inches and screwed them into a square added some 9 inch long 2x2's inside for legs and stained them. Done! Not bad for FREE!!! :)
Look at my Variegated Hostas. I gave them Miracle grow for the first time this year and they loved it!