A pot grown Christmas tree is one that has been planted early on, as a seedling inside a pot filled with compost and growing medium, so that its root ball is completely encased in the container. These are way easier to transplant outdoors or into a bigger pot when compared to potted Christmas trees. A potted tree is one that has been grown in a field and once it has reached a reasonable size has been dug up and transplanted into a pot. Since potted trees have been dug up once before their roots are usually loose in the pot and they don’t normally survive when they’re transplanted outdoors.