The pot without a drainage hole at the bottom is the most common way succulents die in the home. The bottom-line answer is short: succulents need a drainage hole, no exceptions. Either drill one in the pot you already own, use the decorative pot as a cachepot with a smaller plastic pot inside it, or accept that the pot is a vase and not a planter. Here is the rest of the picture.
Part of the Beginner's Guide to Succulents.
Why "carefully watering" a sealed pot does not work
The marketing copy on decorative succulent pots without drainage often suggests you can water lightly, just enough to wet the substrate, and avoid root rot. Three independent mechanisms make this fail in practice.
You cannot measure substrate moisture from outside the pot. The top 2 to 3 cm of substrate dries in 24 to 48 hours indoors; the bottom 5 to 8 cm holds water for 10 to 21 days. The surface gives no signal of what is happening around the rootball. By the time the surface looks dry enough to water again, the lower zone is still saturated. A wooden skewer pushed to the base will tell you, but most owners stop checking after a week.
Excess water pools invisibly. Even a modest 50 ml of water poured onto a 15 cm pot pushes a fraction of that volume past the rootball into the bottom of the vessel, where it has nowhere to leave. That layer sits in direct contact with the lowest roots for as long as it takes to evaporate upward through the substrate column, often two to three weeks indoors.
Salts accumulate. Tap water in most European and North American cities runs 150 to 400 ppm of dissolved minerals (calcium, magnesium, sodium, chloride, sulphate). A drained pot flushes these out at every soak; a sealed pot concentrates them. After roughly six months of weekly tap-water dosing, substrate electrical conductivity climbs above 3.0 mS/cm, and the soluble salt load alone burns root tips chemically before any pathogen arrives.
The combined effect of anaerobic substrate, mineral buildup, and persistent moisture is a textbook setup for Pythium and Phytophthora root rot. The plant looks fine for 6 to 12 weeks, then collapses in a matter of days. This is not a rare failure mode; it is the default outcome.
How big and how many
Hole size and count scale with pot diameter, but the requirements are forgiving:
| Pot diameter | Minimum holes | Minimum diameter each |
|---|---|---|
| Under 15 cm | 1 central hole | 5 mm |
| 15 to 25 cm | 2 to 3 holes | 8 to 10 mm |
| Over 25 cm | 3 to 5 holes | 10 mm |
Total open area should add up to roughly 1 to 2 percent of the pot base. A single 5 mm hole on a small pot is enough because the substrate column above it is short and the water column self-drains under gravity in seconds.
Position matters less than presence. A central hole, an off-centre hole, or multiple smaller holes around the perimeter of the base all work. What fails is one undersized hole partly blocked by the saucer surface or by compacted substrate pressing against it.
Drilling drainage holes
A pot you already own can be drilled cleanly in under five minutes if you match the bit to the material.
Bit choice. A tungsten carbide tile and masonry bit handles terracotta and standard glazed earthenware. Thick stoneware, porcelain, fired stoneware vases, and glass require a diamond hole saw or a diamond pencil bit; a carbide tip will skate across glass and burn out on hard porcelain glaze. Plastic takes any standard 5 to 7 mm twist drill bit.
Speed. Set the drill to its slowest setting, ideally 400 to 800 rpm. Most cordless drills have a low gear or a ceramic-tile setting; use it. High speed (above 1500 rpm) generates frictional heat that cracks glaze rings outward from the hole within seconds.
Water cooling. Pool 3 to 5 mm of water inside the inverted pot bottom, or have a helper trickle water onto the drill point from a syringe or a cup. Cooling is the single most important step on glazed surfaces. Without it, the surface temperature at the bit climbs past 200 °C and splits the glaze before the bit reaches the clay body underneath.
Pressure. Light, steady pressure for two to five minutes per hole. Let the bit do the cutting. Expect dust on dry terracotta, milky slurry on wet glazed ceramic. If the bit smokes or the pot rim is hot to the touch, slow down and add more water.
Setup. Rest the pot upside down on a folded towel on a flat, stable surface. Mark the centre with a felt tip pen. On glazed surfaces, score a small dimple in the glaze with a centre punch or a tap from a steel nail to stop the bit skating; the dimple breaks the glaze in a controlled spot and gives the carbide tip something to bite into.
What does not drill cleanly without specialised tooling:
- Stoneware with wall thickness over about 8 mm.
- Glass of any thickness, including thin terraria, without a diamond hole saw.
- Pots with a metallic foot ring or internal armature.
For these, move to the cachepot strategy.
The cachepot strategy
When drilling is not an option, the decorative pot becomes a cachepot. Plant the succulent in a smaller plastic nursery pot that has its own drainage (typically 4 to 6 holes of 5 mm), then drop that inner pot into the decorative outer one.
Two practical details determine whether the cachepot works or quietly recreates the original problem.
First, the inner pot must not sit on the floor of the cachepot. Any water that runs out of the inner pot pools below it and wicks back up into the substrate by capillary action. Place a 1 to 2 cm layer of inert pebbles, or a small inverted saucer, in the bottom of the cachepot to hold the inner pot elevated; alternatively, use a cachepot with a moulded interior lip that does the same job.
Second, lift the inner pot out for watering, soak it in the sink, and let it drain for 10 to 15 minutes before returning it. Do not water the plant while it sits inside the cachepot, even if the inner pot has its own holes. Water that drains into the cachepot floor will sit there until it evaporates upward, which can take days, and the result is the same as having no drainage at all.
A 1 to 2 cm radial gap between the inner pot and the cachepot wall allows enough air movement to keep the inner pot wall from staying damp through condensation. Snug-fitting plastic pots inside tightly matched glazed cachepots are a common silent failure point.
Mesh, screens, and the broken-pottery myth
A small square of fibreglass insect mesh, a coffee filter, or horticultural shade cloth laid over the drainage hole stops fine substrate falling through without measurably slowing drainage. Any open mesh with apertures above 1 mm is sufficient. Avoid solid materials such as packing tape, which seal the hole entirely.
The traditional advice to put a layer of broken pottery shards or pebbles in the bottom of the pot before adding substrate is wrong, and the experimental work demonstrating this is decades old (Spomer 1974, Bilderback 2005). The hydraulic argument is straightforward: a coarse layer placed below a fine layer raises the perched water table inside the fine layer rather than lowering it. The lowest few centimetres of substrate stay saturated for longer than they would over an open hole, because water cannot bridge the textural break easily and accumulates above it. The "drainage layer" of crocks moves the wet zone closer to the roots, not further away.
Skip the pebbles. Mesh over the hole is enough.
Saucers and the 30-minute rule
A drainage hole that empties into a saucer the pot then keeps sitting in is barely better than no hole at all. Substrate wicks water back upward out of the saucer through capillary action, and the lower 1 to 2 cm of substrate stays saturated.
Empty the saucer within 30 minutes of watering. If the pot is too heavy to lift, set it on three small ceramic feet, wooden cubes, or terracotta pot risers inside the saucer so the drainage hole sits at least 5 to 10 mm clear of the saucer base. This keeps the substrate column out of contact with any standing water that lingers between waterings.
Self-watering reservoirs marketed alongside succulents are the same trap in tidier packaging. The reservoir is engineered to keep the lower substrate continuously damp, the exact opposite of the wet-dry cycle most cacti and succulents need. They suit foliage plants like Spathiphyllum and Pothos; they suit succulents poorly.
When the pot is a vase, not a planter
Some pots cannot be drilled at home: thin porcelain that cracks under any drill pressure, antique ceramics with sentimental or monetary value, glass terraria, sealed concrete planters with metal armatures cast inside. For these, the honest decision is to use them as cachepots only, never as direct planters.
A succulent planted directly into a sealed container can look healthy for 6 to 12 weeks while the rootball quietly fails. By the time the rosette starts to soften or the lowest leaves discolour, the lower roots have already gone, and the recovery process is the full root-rot rescue routine: unpot, wash, cut back to firm tissue, callus for 5 to 10 days, repot in a mineral mix. Many plants do not survive that round trip.
If a friend gives you a succulent arranged in a sealed glass jar or a hole-less concrete cube, the kindest move is to repot the plant into a 10 to 12 cm terracotta or plastic pot with proper drainage within the first week, before damage starts. Use the jar as a vase, a candle holder, or a container for dried botanicals. The plant lives, the gift keeps a role, nobody loses.
See also
- A Beginner's Guide to Succulents: the foundation document for water, light, substrate, and pot decisions that frame any drainage choice.
- Terracotta vs Glazed Ceramic vs Plastic: how pot-wall material changes how much margin a single drainage hole gives you on watering frequency.
- Root Rot in Succulents Diagnosis: the downstream consequence of sealed pots and chronically saturated substrate, with the rescue procedure if you catch it in time.