Mix pigment with matte medium (a paint extender available at craft and art-supply stores) to desired shade -- we combined shades of blue, purple, and white -- and add a little water to thin the paint as necessary, making it easier to work with. It's a good idea to mix a small amount first to find your perfect color, then increase the proportions for a bigger batch.
Use a foam brush to coat the outside of the terra-cotta pots (one coat will do), then let dry overnight. The pigments are strong and will stain your clothes, so mix and apply them carefully.
To hang a pot, just clip a clamp-on hanger onto the lip, and suspend it from a nail or screw on the wall.
All-natural powdered pigments
Nail or screw
Stain pots in colors that complement their contents. Terra-cotta is very porous, so it's important to use materials that won't harm the plants, like the all-natural powered pigments shown.