This is false. Putting gravel, rocks, or other layers of material in your plant pots, planters, or containers with drainage holes does NOT improve potting soil drainage, it instead increases the water saturation level that leads to root rot.
Keeping this in consideration, what do you put in the bottom of a planter for drainage?
Put a layer of gravel in your plant’s drainage tray, or down inside a decorative planter, then sit your plant pot on top. The gravel will hold water and increase humidity, while keeping your plant’s roots up out of the puddle.
Moreover, why do people put rocks at the bottom of pots? Most people will place a stone or pebble over drainage holes in pots, especially the large central ones at the base of terracotta pots, to prevent the potting mix falling out and making a mess.
