Use a container that is shallow and wide. Dwarf varieties, such as 'Chawan Basu' and 'Momo Botan' should be planted in containers at least 24 inches in diameter with a depth of 10-12 inches. Your regular size lotus do best in containers that are 3 feet in diameter. Planting lotus in smaller containers crowds them, resulting in fewer or no blooms.
Place clay soil into your pot. You want to put about 5 inches of dirt into your pot. Any more dirt in the container is unnecessary and may result in the container being too heavy to move. Then place the lotus tuber on top of the dirt with the cut edge of the rhizome against the edge of the pot.
Next take a flat rock and place it on top of the tuber. It isn't necessary to put dirt on top of the tuber. It will grow down into the dirt. The rock just keeps it positioned and keeps it from floating to the top of the container. You would next add about 2-3 inches of water to cover the tuber. Keep the container in a warm sunny location as the plant establishes itself. You will need to add water to compensate for evaporation as necessary. Once the lotus has produced several leaves, a shallow layer of soil may be added to cover the tuber, but isn't necessary. You want to be careful so you don't break the growing tip. At this point you can add a small gravel topping if desired.
Once the lotus has several leaves you can begin to lower it into your pond making sure you don't put the leaves under water. Eventually getting the container to the depth you want it. You can be quite successful growing a lotus in the container sitting on your porch or deck without putting it in a pond. Just make sure you keep adding water as it evaporates.
Now sit back and enjoy the fruits of your labor.