Clay Pots
If you want to seal a clay pot so you can apply mosaic materials, or if you simply want to cut down on the water loss through the pot wall, there are many products designed for this purpose. For instance, if you Google “How to seal flower pots,” you will see a product called “Clay Pot Sealer” that is available at Walmart. The site also explains how to apply it. If you have left over granite or grout sealer around, that will also work.