Citrus trees grow well in terracotta pots or containers. Terracotta is porous, which allows roots to breathe. It also reduces the risk of the citrus tree becoming waterlogged. Terracotta can help you gauge the amount of moisture in the pot—tap a wet pot, then a dry pot, and listed to the difference in sounds that they make. You may also notice a darker color to the terracotta of the wet pot. These are your clues as to whether your plant needs watering or not.
Always choose a pot without an inside lip—you never know when you might need to re-pot, and inner lips make it that much harder to get your root ball out in one piece. Container-planted citrus trees can be vulnerable to damage in high winds, especially if they have a lot of foliage.
If your tree is knocked down, terracotta pots tend to crack. To minimize the possibility of this happening, fill the pot most of the way with soil and compost, then top-dress it with a generous inch of horticultural grit. This grit will do double-duty for you: first, it will prevent weed growth in the pot; second, it will weigh it down considerably and help prevent blow-overs. (Of course, this will also make it more difficult to move—although you have the option of removing the grit, moving the pot, then replacing it.
Regardless of the type of pot you use for your citrus tree, make sure it has a large, central drainage hole in the bottom. To improve drainage in your pots, arrange small, broken pieces of terra cotta in the bottom before filling with soil and compost.
One of the most common mistakes people make when potting citrus trees is over potting. Using too-large a pot won’t make your tree grow faster! It will just cause additional, unnecessary work for you.
Large containers used for trees should be at least 30 inches (75 cm) high and 40 inches (100 cm) across. Larger is better, but they should not be so tall that they become unstable in wind. It is also good practice to move permanent container plants of borderline hardiness into sheltered spaces in winter, and move very tender specimens indoors.
You will find full details about how to grow citrus trees in containers and pots in Grow Citrus: The Insiders Secrets to Growing Great Citrus