Terracotta planters and frost: what survives a Swedish winter

Terracotta and frost have a complicated relationship. The material is porous, which means water gets in. When that water freezes, it expands, and if the walls of the pot are not thick enough or the clay not dense enough, the pot cracks. In Sweden, where temperatures can swing from -15°C to +5°C in the same week, this is a real risk. Here is what the ratings mean and what to do in practice.

Frost-resistant versus frost-proof ¶

Frost-resistant means the pot has been tested to withstand freezing temperatures down to a stated minimum. In our case, -8°C for the terracotta planters from the Alentejo workshop. Below that temperature, or in repeated freeze-thaw cycles, cracking is possible.

Frost-proof is a stronger claim and usually applies to high-fired stoneware or vitrified ceramics. True frost-proof pots can handle Swedish winters outdoors without cracking, but they are heavier and more expensive. We do not currently stock a frost-proof outdoor planter. This is something we are looking at for the spring 2027 range.

What to do with terracotta in autumn ¶

The safest approach is to bring terracotta planters indoors before the first frost, which in central Sweden (Örebro latitude) typically arrives in October. If you want to leave them outside, empty them of soil first. Wet soil expands when it freezes and can crack the pot from the inside even if the exterior would otherwise survive.

If you are leaving a planted pot outside, raise it off the ground on pot feet to allow drainage and reduce the contact area with frozen ground. Wrap the pot in horticultural fleece if temperatures are forecast below -5°C for more than two consecutive nights.

The stoneware planters: indoor only ¶

The grey-green glazed stoneware planters from the Algarve studio are sealed at the base and have no drainage hole. They are designed for indoor use and should not be left outdoors in Swedish autumn or winter. The glaze is not rated for frost and the sealed base will hold any water that gets in, accelerating freeze damage.

Product pages for all our planters state the frost tolerance clearly. If you are unsure about a specific pot and your outdoor conditions, email us before ordering.