Answer: Sounds as though you're doing everything right for your gardenias. I garden in containers and have found that they can dry out quickly so I check them at least once a day and sometimes twice a day to make sure they have enough moisture. I can tell by picking up the containers; heavy ones have moist soil and lighter ones need to be watered. You can also check by sticking your finger into the potting soil. If it is moist about an inch below the surface, it won't need to be watered for a while. In containers, the potting soil can dry unevenly and pockets of dry soil can develop within the rootmass. Then, no matter how frequently you water, the water can just flow right through to the drainage holes without thoroughly wetting the soil. So, I place the container in a larger container of water and allow it to set for about 15 minutes. This saturates all the soil. I do this once every 2-3 weeks. Now for "leaching". Sometimes containerized plants get a build-up of salts and minerals from fertilizer applications. You can leach the excess minerals out of the soil by immersing the pots in a larger container of water until the soil is fully saturated. Do this every 3-4 weeks during the growing season. If you do, you'll kill two birds with one stone - you'll leach out excess minerals and you'll eliminate pockets of dry soil within the root mass.
Hope this clarifies things for you!
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