- Canvas as plant cover crop, necessarily filtering.
- Pebbles, stones, or better, pozzolana (volcanic rock),
- Mixture of compost, ground and sand.

Contrary to some beliefs, citrus fruits are relatively rustic plants which are only afraid of long-lasting cold.
Orange tree in a pot cannot draw nutrious elements which it needs in the ground.
It’ll draw its stocks and its food in the pot and in the ground you’ll bring it.