A well-chosen pot is never just a container. In the gardens I work with across Belgium — from contemporary terraces in Brussels to large private estates in the Brabant Wallon — pots are sculptural objects in their own right. They punctuate a terrace, frame an entrance, create rhythm on a stone surface. A beautiful glazed stoneware pot placed at the end of a sight line carries the same compositional weight as a sculpture. It deserves the same attention.
And yet pots are often the most neglected objects in the garden. Terracotta cracks. Glazed surfaces cloud over. Concrete stains. Zinc corrodes unevenly. None of this is inevitable — it's almost always the result of a few overlooked gestures. Here's what to do, material by material.
Terracotta: beautiful, porous, and worth the extra care
Unglazed terracotta is one of the most timeless materials in garden design. Its warmth, its natural texture, the way it ages into ochre and rust tones — these are qualities no synthetic material can replicate. But terracotta is porous by nature, and that porosity is both its charm and its vulnerability.
Water penetrates the walls. In winter, that water freezes, expands, and splits the clay from the inside out. A pot that survives ten Belgian winters isn't lucky — it's been properly cared for.
During the season: never let water sit in the saucer for more than a few hours. Lift the pot slightly on feet or wedges to allow air circulation underneath and prevent contact moisture on your paving. Remove algae and limescale deposits with a soft brush and lukewarm water — no abrasive cleaners, no high-pressure washing, both of which erode the surface and accelerate water penetration.
Before winter: for pots without a frost-resistance guarantee, bring them inside or wrap them in horticultural fleece. Even frost-certified pots benefit from being raised off the ground — direct contact with a frozen surface draws cold into the base faster than air temperature alone. Always empty saucers completely before the first frost.
A note on new terracotta: before first use, soak the pot in clean water for a few hours. This saturates the walls and reduces the initial pull on your potting mix — your plants will establish more easily in the first weeks.
Glazed stoneware: robust, but the glaze tells the whole story
Glazed stoneware — fired at temperatures between 1,200 and 1,300°C — is significantly more resistant than raw terracotta. The vitrified glaze seals the surface, making it essentially waterproof and far less vulnerable to frost. It's the material most suited to large statement pots on a contemporary terrace, and the backbone of the potscaping approach — using large pots as structural design anchors rather than decorative afterthoughts.
Routine cleaning: a rinse with clean water and a wipe with a soft cloth is enough in most cases. For stubborn marks — mineral deposits, dried soil, green algae — use a non-abrasive sponge with a small amount of washing-up liquid. Rinse thoroughly. Avoid bleach or acid-based products, which dull the glaze over time.
What to watch for: hairline cracks in the glaze, particularly at the base of the pot. These can appear after impact or repeated freeze-thaw cycles. Once the glaze is breached, the stoneware beneath behaves like unglazed terracotta — absorbing moisture and becoming frost-vulnerable at that point. Inspect the base of your pots each spring.
Wintering: quality glazed stoneware can stay outside year-round without issue. Decorative-grade pieces — thinner walls, lower firing temperatures — should be treated with more caution. When in doubt, bring them in from November.
Concrete and cast stone: embrace the patina, manage the staining
Concrete planters sit naturally in mineral garden compositions — alongside slate terraces, corten steel structures, and architectural planting. Their mass gives them presence. Their texture deepens with age. But in Belgium's damp climate, moss and algae colonise porous surfaces quickly if left unattended.
Regular brushing: a stiff brush and cold water used every few weeks during the growing season prevents the build-up that becomes difficult to shift once established. For ingrained green deposits, a diluted white vinegar solution (50/50 with water) applied for a few minutes before rinsing is effective and gentle on the material.
Sealing: applying a concrete or stone hydrophobic sealant once a year significantly slows moisture absorption and surface growth. It's a 20-minute job that can double the presentable life of a concrete planter.
Replanting hygiene: when emptying a concrete pot between plantings, clean the interior before refilling. Residual soil stains permanently once dry, and can harbour pathogens that affect the next planting. A quick scrub while the pot is still moist takes very little time.
Zinc and metal: let it age, but on your terms
Zinc troughs, corten steel containers, powder-coated metal planters — these materials have become defining elements of the contemporary garden aesthetic. Their tonal range, from warm rust to cool grey-blue, works exceptionally well against disciplined planting and stone surfaces. But metal requires a different kind of attention than ceramic or stone.
Zinc: natural patination is part of the material's appeal — do not try to restore the original bright finish. What to avoid is accelerated, uneven corrosion from prolonged contact between the exterior wall and wet soil. Keep zinc pots raised off the ground at all times.
Corten steel: the rust surface stabilises once fully formed and requires no maintenance. The practical concern is run-off: corten will leave rust streaks on pale paving or light-coloured stone during its initial oxidation phase. Ensure drainage doesn't flow directly across valued stonework, or use a drip tray in the first season.
Powder-coated or painted metal: inspect annually for chips and scratches, which expose bare metal to oxidation. Touch up promptly with matching metal paint — a small scratch ignored for one season can become a rust patch that compromises the whole surface by the following year.
Rules that apply to every material
Beyond the specifics of each surface, a handful of principles apply universally — and ignoring any one of them is almost always the root cause of premature deterioration.
- Drainage is non-negotiable. A pot without a functioning drainage hole holds water at the root zone, kills plants, and degrades the pot from the inside. Check drainage holes every spring and clear any blockages before planting.
- Raise pots off the ground. Even a centimetre of clearance — pot feet, a thin slate tile, discreet wedges — improves air circulation, prevents moisture damage to the base, and avoids contact staining on your paving.
- Clean between plantings. Old potting mix is depleted, often compacted, and may carry disease. Empty, scrub, and refill with fresh substrate each time you replant. The difference in plant performance is visible within weeks.
- Store empty pots under cover in winter if their frost resistance isn't guaranteed. An empty pot freezes faster than a planted one — the substrate provides thermal mass that an empty vessel simply doesn't have.
The pot as a long-term investment
At Art for Garden, the objects we curate are chosen for their durability as much as their beauty. A hand-thrown glazed stoneware pot from a skilled ceramicist, a cast stone planter with genuine mineral aggregate, a zinc trough formed by a metalworker — these aren't seasonal accessories. They are investments in the permanent character of an outdoor space, much like the stone sculptures that have anchored gardens for centuries.
That investment only holds its value with basic care. The gestures described here are simple, low-effort, and almost entirely preventive. A pot that is cleaned, drained, raised, and occasionally sealed will outlast its owner. One that isn't will look tired within three seasons.
If you're interested in how large pots can structure an entire terrace composition — rather than simply fill corners — our piece on potscaping with large terracotta pots is the natural companion to this one. And if the broader question of how art and living material coexist in the garden interests you, The Garden as Living Art takes that conversation further.
Questions about a specific material, or about the pieces in our collection? Get in touch — we're happy to advise.
FAQ — Garden pot care
Can glazed pots stay outside through a Belgian winter?
Quality glazed stoneware fired above 1,200°C can generally stay outside year-round. The key conditions: ensure full drainage, raise the pot off the ground, and never leave water in the saucer before a frost. Decorative-grade pieces with thinner walls are better brought inside or protected from November onwards.
How do I remove white salt deposits (efflorescence) from terracotta or concrete pots?
These white crusts are mineral salts migrating outward through the pot wall with moisture. Brush dry first to remove the loose deposit, then apply a 50/50 solution of white vinegar and water, leave for five minutes, and rinse thoroughly. A hydrophobic sealant applied afterwards will significantly slow the recurrence. Avoid acidic descalers or bleach, which can damage the pot surface and any nearby planting.
Should I prepare a new terracotta pot before planting?
Yes — soak it in clean water for a few hours before planting. Dry terracotta pulls moisture aggressively from the potting mix, which can stress young plants in the first weeks. Soaking the walls first saturates the clay and gives your planting a more stable start. Particularly worth doing for large pots where refilling later is inconvenient.