Corten steel square planters

For squares as tall as they are wide (the 1200 mm square stops at 1000 mm high), the table shows what each model offers. Prices are for the base finish, our signature patina; the weight is the empty weight shown on the product page, and the volume is the outside volume.

At 400 mm the two Cybèle versions are only £10 apart (£740 and £750). From 800 mm a side the choice narrows to the 2 mm Cybèle, which sits flat, and Thalie, which stands on legs.

Start from the root ball of the plant as it comes from the nursery: the cube should be clearly wider and deeper, so that a layer of compost surrounds the roots and sits beneath them. A young olive or a citrus in its container settles well in a cube of 600 to 800 mm; a more mature specimen calls for 1000 mm a side or more. Think about growth as well: repotting a tree that stands in 500 kg of soil is not a simple job, so it is worth choosing the larger cube from the start.

Height is a matter of proportion as much as of roots. A low cube (400 mm) works as a plinth for a spreading plant; a tall square (800 to 1000 mm) lifts the foliage and gives a trailing plant room to cascade. Cybèle 2 mm covers both, from 400 to 1400 mm a side and from 400 to 1000 mm high. If the height matters more than the footprint, our tall Corten steel planters set out the column sizes.

• Cybèle 1.5 mm: 7 sizes up to 700 mm a side, including 400 × 400 and 500 × 500 mm columns standing 1000 mm tall.
• Thalie: squares from 600 to 1400 mm a side on four corner legs, which lift the planter off the ground.
• Maïa: 800 × 800 × 300 mm (£900) or 1200 × 1200 × 300 mm (£1,190), divided into compartments to keep herbs, perennials or vegetables apart.

Two identical cubes either side of a front door, a gate or a flight of steps frame the way in. Choose a size in proportion to the opening: for a front door that is often 500 to 700 mm a side. In a row, repetition does the work: three, five or seven cubes of the same size, evenly spaced, give rhythm to a path or the edge of a patio better than a continuous line when you want to keep the view between the plants.

For a looser arrangement, combine two heights with the same footprint, for example 600 × 600 × 400 and 600 × 600 × 800 mm: the faces stay aligned and the change in level creates depth. In a small town garden, one generous cube placed off centre often gives more structure than several small pots. Line the planters up while they are empty: once filled, they will not move.

On a roof terrace or a balcony, remember that a filled cube weighs far more than its empty steel. Have the structure checked before choosing the larger sizes, and place the heaviest cubes where the structure is designed to carry them.

We apply the Cortenys signature patina in the workshop: each cube arrives already patinated, and its tones keep developing with exposure. Rainwater running down the four faces can leave a rust-coloured line around the planter on pale paving or stone, especially in the first months.

We offer a protective varnish as an option on all four models. The protective varnish greatly reduces run-off, but even varnished, Corten steel can still stain the floor: stand the cube on small feet, spacers or a saucer, surround it with a strip of gravel, or set it on a dark slab. Thalie, raised on its legs, limits contact between its wet base and the paving. Our guide to Corten steel care and rust stains goes through these precautions in detail.

A square sets one plant apart; for a hedge or a continuous border, our Corten trough planters are the better fit. If the cube is to be planted straight into the ground, Rhéa keeps the square shape without a base, among our Corten steel bottomless planters. Squares of 1000 mm a side and more are compared on the page for large Corten steel planters, and every shape is set out across our Corten steel planters.