Well, first you'll need to find a suitable planter that's the right size for your tree. Make sure it's deep and wide enough to accommodate the tree's roots and branches. Next, fill the planter with potting soil and gently place your tree inside. Water it regularly to keep the soil moist but not too wet. Finally, decorate your planter to make it look festive and inviting. Voila! You've got yourself a Christmas tree in a planter.