When you’re planting into a into a larger plant pot, you should choose a pot that is either one, or ideally two, sizes larger than the existing pot. To make it easier for you when potting on, water the plant in its existing pot about half an hour before hand. The plant will then be easier to remove from its existing pot without damaging its roots. If you do find that the roots of the plant have started to coil around when they’ve reached the bottom of the pot, gently ease the roots out before planting into the new plant pot.