Planter Drainage Holes: Bottom vs Side Placement

Bottom drainage holes are the standard

For most planters, the drainage opening belongs at the lowest point of the container. Gravity pulls excess water down through the soil, and a hole at the base lets that water leave completely, so the root zone does not sit in a puddle. The Old Farmer's Almanac makes the same point: a container should have a drainage hole or some other way to allow water to pass through it, because water-logged soil promotes bacterial and fungal growth that stunts plants.

A hole exactly on the bottom face only works if the planter is lifted off the surface it rests on. If the pot sits flat on a patio or shelf, the hole seals against the surface and water has nowhere to go. That is why many planters include small feet or a recessed base, which you can read about in planter feet and clips and the recessed base.

How side holes change water removal

Side holes sit on the vertical wall of the planter, usually close to the floor. Water can drain through them only down to the level of the lower edge of the opening. Any water below that edge has no exit unless the inner base slopes toward the opening, a detail covered in the inner base slope.

The side placement is common on wall planters and window boxes, where the back of the pot mounts against a surface and a bottom hole would be against the wall. Arcadia Garden Products is one maker that offers wall planters as a dedicated category, and Austram lists decorative planters and hanging baskets. For these designs, a side opening is the practical choice because the lowest face is not open to air.

What placement means for root health

Roots need oxygen as much as they need water. When the lower part of the pot stays saturated, the soil becomes water-logged, and as the Almanac notes, that promotes bacterial and fungal growth and stunts plants.

A bottom hole with the planter raised lets the whole column drain. A side hole can leave a permanent puddle below the opening if there is no slope, and that puddle is exactly the water-logged condition the Almanac warns about. For most houseplants and vegetables, the goal is complete removal of excess water, not a reservoir at the base.

If you notice these signs, the first fix is to raise the pot and confirm the hole is open. If the hole is on the side, check whether the inner base is level; any slope toward the opening helps. Exposure to air at the opening also encourages roots to branch instead of circling, which is covered in planter root air pruning.

• Soil that stays wet long after watering
• Roots that smell or turn brown
• Slow growth despite good light

Choosing by where the planter sits

Indoors, a bottom-hole planter needs a saucer to protect floors; see planter saucer need. On a deck or wood surface, a side hole can direct water away from the surface, but the stream may still stain, so a saucer underneath is a good safeguard.

Outdoors on soil or gravel, the position of the hole matters less, but a planter with feet still drains more reliably. For self-watering planters, the reservoir is intentional and the drain sits above the reservoir level; see best self-watering planters.

What to look for when buying

Check where the hole sits in relation to the inner floor. A hole at the lowest point with raised feet or a recessed base is the most forgiving. A side hole works if the inner base slopes toward it or if the base is recessed to collect water below the opening. Sizing matters too: see drainage hole size and drainage hole spacing.

Planter families differ. Ceramic pots usually have a single bottom hole, plastic and resin planters are molded and often include feet and multiple openings, and wall or window planters use side openings. Makers cover both arrangements: Arcadia offers wall planters, Austram lists decorative planters and hanging baskets, and Suncast manufactures molded resin planters from domestically sourced resin.

For general use, a plastic planter with bottom holes or a ceramic pot with a matching saucer will behave predictably. For larger outdoor statements, see best large outdoor planters.

Holes you can adjust

Some planters include removable drainage plugs, so you can open the hole for outdoor use and seal it when you move the pot indoors. The plug sits in the bottom or the lower side wall, and it changes the same trade-offs described above. See planter drainage plug for how these work.

If you prefer to keep the opening open on a side-hole planter, a plug left in place converts it to a reservoir-style pot, which is useful for self-watering setups but risky for plants that need dry roots.

What to pick for your use

Questions

Do side drainage holes work as well as bottom holes?

For most plants, no. Bottom holes drain the full soil column, while side holes leave water below the opening unless the inner base slopes toward the hole. Side holes make sense for wall planters and some self-watering designs.

Why do some planters have side holes instead of bottom holes?

Side holes are used when the bottom face sits against a surface, as in wall planters or window boxes, or when the design keeps a small water reserve below the opening. The trade-off is that the area below the hole can stay wet.

What happens to water that sits below a side hole?

It stays in the pot unless the base slopes or a lower drain exists. That saturated layer can promote bacterial and fungal growth, as the Old Farmer's Almanac warns.

Should you use a saucer with a side-hole planter?

Yes, if you want to protect the surface underneath. A side hole lets water run out sideways, so a saucer catches it, and you can empty it regularly.

Can you drill a side hole into an existing planter?

You can add openings to plastic and resin planters, but drilling ceramic or terracotta risks cracking. Place any new hole low, leave enough wall below it, and keep the opening at or above the inner floor.