What is the best container for houseplants?

There is a difference of opinion. Ordinary red clay pots are generally best because they have bottom drainage holes, and the porosity of the clay permits some air to reach the soil. But they are challenging to keep clean and require frequent watering. Painted clay pots and plastic pots also have bottom drainage, and they do not get encrusted with salts and dirt, but they permit no soil aeration. Glazed containers are the most handsome and easiest to clean, but they do not admit air to the soil, and most of them do not have drainage holes.