Large Corten steel planters

Outside dimensions, the empty weight listed on each product page, and the US price in the base finish (our signature patina). The outside volume (L × W × H) gives you the scale; the amount of soil you can actually fit is a little less.

With a large planter, the weight is in the soil, not the steel. Depending on the mix and how much water it holds, moist potting soil weighs roughly 1 to 1.8 kg per liter (about 8.3 to 15 lb per US gallon); your soil supplier can give you the exact figure. Filled all the way, that works out to:

• Cybèle 2 mm, 1000 × 1000 × 400 mm: about 400 L (106 US gal), so roughly 400 to 720 kg (880 to 1,590 lb) of soil, plus 43.3 kg (95 lb) of steel.
• Déméter 2 mm, 2000 × 500 × 1000 mm: about 1000 L (264 US gal), so roughly 1 to 1.8 metric tons (2,200 to 3,970 lb) of soil, plus 106.2 kg (234 lb) of steel.
• Cybèle or Thalie, 1400 × 1400 × 1000 mm: about 1960 L (518 US gal), so roughly 2 to 3.5 metric tons (4,300 to 7,800 lb) of soil, plus 120.7 to 124.1 kg (266 to 274 lb) of steel.

On a concrete patio, a gravel pad or right on the lawn, these weights are mostly a matter of handling. On a wood deck, a porch, a balcony or a rooftop, they become a matter of structure: a large planter, once filled, can top 1 metric ton (2,205 lb) on less than 2 m² (about 21 sq ft). Only a structural engineer or a contractor who knows the structure can tell you whether it will carry that load. Give them the outside dimensions, the empty weight and the estimated soil volume of the format you are considering.

If the load is the limit, cut the height before the footprint. On the same square, going from 1000 mm (39 in) to 600 mm (24 in) high removes 40% of the volume, and plenty of plants never use that much depth. Maïa, only 300 mm (12 in) high, covers 1200 × 1200 mm (47 × 47 in) with 432 L (114 US gal), divided into compartments for a deck-side herb or perennial bed.

Before you order a 1400 mm (55 in) square or a 2000 mm (79 in) trough, walk the route to its final spot and measure every gate, side yard, doorway, step and tight turn. The planter goes in empty, and even empty it weighs 37.5 to 124.1 kg (83 to 274 lb) depending on the format: plan on two to four people to carry it. On a sloped yard, prepare a level, firm base first, such as a compacted gravel pad or pavers.

With the planter in position, check that it sits level; the soil goes in last, because once filled it stays where it is. For a big volume, lay a drainage layer at the bottom and landscape fabric over it, then add the soil in layers to limit settling, watering each layer as you go. Our guide on how to choose a Corten steel planter walks through the other decisions to make before you buy.

The large squares, 1000 to 1400 mm (39 to 55 in) across, hold a small tree (an olive, a Japanese maple, a multi-trunk specimen) with ground cover underneath. The long Déméter troughs, 2000 mm (79 in) long and 500 or 600 mm (20 or 24 in) wide, take a privacy screen of evergreen shrubs or clumping bamboo along a property line or the edge of a deck. Leave a little room below the rim so water does not spill over when you irrigate. For a single tree in a round pot rather than a box, see our large Corten steel pots: Callisto, Clio and Calypso from Ø 800 mm (31 in).

For layouts that pair large planters with paths, seating and fire, browse our Corten steel garden ideas, or see how a planter can sit next to one of our Corten steel fire pits.

A large planter has a lot of wall surface, so more rain runs down the steel while the patina develops. Around light concrete, limestone or a pool deck, set it on shims or a gravel border, as our Corten care and rust stain guide explains.

Each model on this page also comes with our protective varnish, for instance $3,700 for Déméter 2 mm in 1500 × 400 × 400 mm (59 × 16 × 16 in) or $4,240 for Cybèle 2 mm in 1000 × 1000 × 400 mm (39 × 39 × 16 in). The varnish greatly reduces runoff, but even varnished, Corten steel can still stain the floor: keep the shims, a gravel border or a dark paver under a large planter whichever finish you choose.

In the yard, a large volume set on open ground does not always need a base: our bottomless Corten steel planters let roots grow down into the native soil and spare you hauling tons of potting mix. On a deck, a porch or a rooftop, keep a planter with a base.

For a long, slim run, see our Corten steel trough planters; for a single specimen tree, our square Corten steel planters; for height without width, our tall Corten steel planters. Every size is in the full collection of Corten steel planters.