Terracotta is the traditional material for a window box and still the best-looking on a period frontage. Because the clay is porous, compost in a shallow trough (the hardest kind of container to keep healthy) dries evenly rather than staying sour at the bottom. The Antico pieces are aged in the making, which suits a Victorian or Georgian frontage where a new-looking box would sit awkwardly. Roma, Garda and Liscia give plainer profiles for a cleaner elevation. Arena Venezia is the more decorative of the group.

Measure the sill, not the window: a box should sit close to the full width of the opening to look deliberate, and the sill is often narrower than you think. A planted terracotta trough is heavy, and heavier once watered; above a pavement it needs securing properly. We can advise on brackets in the shop.