People use pottery planters for container gardening all over the world. Their surface is porous, and every inch is meant exclusively for planting. These planters require drainage holes at the base, which you must drill if they lack them.
Touch the surface of your planter to determine whether it is glazed or unglazed so you know what kind of drill bit to use. Glazed pottery planters have a thin film of glaze covering them that is so hard it can actually scratch metal. Such planters have a smooth texture and shiny surface.
Unglazed planters are the terra cotta planters commonly used for gardening. This unglazed earthenware is red clay that is low-fired and easy to drill into.
Turn the planter over and mark drainage holes on its base with a marker or pencil, spaced at least 6 inches apart.
Insert a carbide masonry bit in an electric drill if the planter is unglazed. Wear your earplugs and protective goggles and place the tip of the bit directly over the hole mark.
Press the trigger of the drill so it starts puncturing the surface of the pottery planter. Avoid applying too much pressure as that may break the planter, but keep a steady hand and work at a slow pace until your drill bit comes out from the other side of the planter surface. Blow on the surface to remove any residue, and make the other holes the same way.
Insert a drill bit specifically meant for drilling through glass or tile if making holes in glazed pottery planters. Such bits have a special tip specifically meant for aggressive drilling but without the pressure, and these are available at most hardware stores.
Apply a layer or two of masking tape over the marker or pencil mark on the glazed surface to prevent the drill bit from slipping off the smooth surface.
Position the tip of the drill bit over the masking tape, press the trigger and drill at a slow and steady pace, until the tip comes out from the other side. Repeat the procedure for drilling other holes on the planter.