If you are using these pots for plants that have high water requirements or don’t respond well to the wetting and drying cycle, sealing your terracotta pots is worthwhile. You can either seal the inside or the outside of the pot. … Always give the paint/sealer a couple days to fully dry before planting.
One may also ask, how do you keep ceramic pots from cracking?
Use gloss Mod Podge for a shiney hard finish. Seal the inside of the pot as a final coat to prevent water seeping and cracking the design. Pick a paper napkin in any pattern you want, this technique will work to make any style or size pot.