Rope - I'll be using 1/8" cotton rope. You'll need 120 feet for this plant hanger. I buy it by the spool (1200 feet) at knot and rope supply: http://bit.ly/14wi43K
Electrical tape - I'll use this to whip the ends of the rope so they don't unravel as we tie. Electrical tape is flexible and meshes well with the rope.
Thimble - This is a 5/16" thimble. You should be able to pick one of these up at any local hardware store.
1.5" diameter wooden ball - I'll be using this at the very end as the core for the final knot. You can get them at any local craft store. The one I have has a flat bottom, but any ball will do.