Large pots can take a huge amount of costly potting soil and weigh so much they are hard to move. At the end of the year when you remove the plants, you find that the majority of the roots don’t get anywhere near to the bottom of the container.
Use some of those empty containers the plants come in from the greenhouse. It will make for great drainage, help the plants get enough air to the roots and save on potting soil cost and weight.
Those empty 4-inch pots work especially well turned upside down and lined up on the bottom. Just cover with your preferred potting soil mix and fill with your plants.