Metal plant pots: Corten steel or aluminium

We took from our product pages the sizes offered in both materials. For Callisto, the size reads diameter × height; for Clio, top diameter / bottom diameter × height; for Daphné, opening × height. Weights are the empty weights shown on each product page; prices are UK prices in the base finish, our signature patina for Corten and black RAL 9005 for aluminium, which costs the same as its seven other colours.

Size for size, the aluminium pot weighs about half as much as its Corten steel twin: 1.86 to 1.95 times less depending on the size, even though its 3 mm wall is thicker than the 2 mm of the Corten. A Callisto of Ø 800 × 800 mm drops from 41.4 kg to 21.4 kg.

On price, the gap is modest in our UK prices: aluminium costs 1.24 to 1.44 times as much as Corten steel. On Callisto, it is smallest at Ø 600 × 600 mm (£1,130 against £910) and widest on the narrow Ø 350 mm column, 1000 mm tall (£1,210 against £860). Daphné ranges from 1.26 times in its smallest size to 1.44 times in its tallest, and Clio stays between 1.33 and 1.39 times.

The real difference lies in the choice of sizes. We offer our Corten steel pots in far more dimensions, and wider ones:

• Callisto: 23 sizes in Corten steel, from Ø 350 to Ø 1400 mm and from 400 to 1000 mm tall; 9 sizes in aluminium, up to Ø 1200 mm. The Corten sizes from Ø 800 mm are compared on our page of large Corten steel pots.
• Clio: 13 sizes in Corten steel, with a top diameter of 500 to 1000 mm; 3 in aluminium, including a 600 / 400 × 600 mm size offered only in that metal.
• Daphné: the same 4 sizes in both metals, from 600 to 1200 mm tall (see Daphné in aluminium).
• Calypso, our conical pot with a wide rim, comes only in Corten steel, in 12 sizes from Ø 600 to Ø 1000 mm: you will find it among our Corten steel pots.

Where every kilo counts, aluminium has the edge. A pair of 600 × 600 × 1200 mm Daphné pots framing a set of French doors weighs 79.4 kg empty in Corten steel, against 42.8 kg in aluminium. A Ø 350 × 600 mm Callisto in aluminium, at 6.5 kg, can be moved with one hand as the seasons change.

These are empty weights. Filled with damp compost, a pot weighs far more than its metal, and it is the soil that makes up the load. On a balcony or a roof, have the permitted load checked by a professional before you install large volumes; our guide on how to choose a Corten steel planter is a reminder that wet soil weighs far more than steel.

In the ground, on a lawn or beside a path, the weight of Corten steel becomes an asset: a large pot planted with a shrub stands up better to the wind.

Corten steel arrives with the signature Cortenys patina applied in the workshop: shades of rust, sienna and amber unique to each pot, which deepen with the seasons. It flatters silver foliage, ornamental grasses and warm-coloured flowers.

In aluminium, each pot comes in eight colours at the same price, with a 30% gloss: White RAL 9016, Grey RAL 7016, Black RAL 9005, Blue RAL 5001, Yellow RAL 1005, Green RAL 6018, Red RAL 3020 and Orange RAL 2004. A black or grey pot underlines contemporary architecture; white brightens a shady courtyard; a bold colour makes a statement at the front door.

Both metals are delivered bare, ready to plant. If a plant dislikes heat, line the inside with insulation or a thick geotextile: in full sun, any metal warms up.

Corten steel can leave rust run-off on pale stone, paving or a pool coping, especially in its first months. The protective varnish we offer as an option on our Corten pots greatly reduces it without ruling it out: even varnished, a Corten steel pot can still stain the ground. Stand it on a saucer, spacers or small feet, or on a bed of gravel. Our Corten steel care guide covers these precautions.

Powder-coated aluminium does not rust and leaves no rust marks. It is the metal we recommend beside a swimming pool, on very pale paving and by the sea, where salt stops the Corten patina from stabilising; our guide to Corten steel near the sea explains why.

Start with the spot, then the size of the plant.

• Balcony, roof terrace, a pot you will move: aluminium, half the weight.
• Pool surround, pale paving, the coast: aluminium, with no rust run-off.
• A colour to match a façade or window frames: aluminium, in eight colours.
• A very wide pot for a tree or an olive: Corten steel, up to Ø 1400 mm with Callisto; our large Corten steel planters are another option for a tree.
• A tall, narrow pot for an entrance: Callisto at Ø 350 mm or Daphné, in both metals, or our tall Corten steel planters.
• A tighter budget and a material that changes over time: Corten steel, from £780 for Callisto.