You can paint terra cotta or clay pots with acrylic paints. But if you do not seal the pots after painting, the paint does not last in the sun. Once paint dries, apply the correct sealant to provide the pot with a protective matte or glossy finish to over the paint, making it suitable for indoor or outdoor use.
Preparation: You'll need newspaper or a plastic table cloth, 400-grit fine grain sandpaper, soap, water and a towel to prepare the pot for painting.
Paint: Pick up an acrylic primer and water-based acrylic paints in your desired colors. Regular craft acrylic paint works, or you can use outdoor acrylic paint -- often called patio paint. Use paintbrushes and sponges to apply the paint. For decorative touches, paint over stencils to add flowers, shapes or other accents to your pots.
Sealant: After painting, you'll need a can of spray clear coat indoor-outdoor acrylic sealant or another similar product. Wear a mask to cover your nose and mouth while applying the sealant.
Cover your workspace with newspaper or a plastic table cloth. If your pot was previously used for planting, remove the plant and wash the pot with soap and water. Verify the exterior of the terra-cotta pot is clean and dry both inside and out. If any potting soil is left on the area where you plan to paint, the paint will not adhere as well.
With fine-grain sandpaper, gently smooth the surface of the terra cotta, and then wipe with a damp cloth to remove dust. Let the pot dry completely before painting.
Paint the terra-cotta pot inside and out with a neutral primer coat of paint. Terra cotta is very porous, and will absorb some of the paint. The base coat helps to seal the pores, as well as cover the terra cotta's natural orange-brown color, making the decorative paint stand out brighter. After the primer coat dries sufficiently, add artistic designs in your desired colors, repeating with a second coat if necessary. Let dry completely between coats. Use sponges and stencils to add decorative touches, using at least two coats for stencils to make colors pop. Let the pot dry completely.
Once the paint dries, cover an outdoor or well-ventilated area with newspaper or a plastic tablecloth -- do not use spray paint in enclosed spaces. Put on a face mask and follow the directions on the can of indoor-outdoor clear-coat acrylic sealant to apply a layer of sealant to the inside and outside of your pot. Hold the spray can at least 8 to 12 inches from the surface as you spray it. Let it dry completely and then apply a second coat. Let dry at least 24 hours before adding soil and plants. When painting and sealing your pot, do not neglect to paint and seal the inside. Because terra cotta is so porous, if the inside is not sealed, it will absorb water and compromise the paint on the outside of the pot with time.