Do.

Rest containers on an insulating base such as a 10–20 mm sheet of closed-cell foam (camping mat or garden mat), a piece of expanded-polystyrene (EPS/XPS) with drainage slots cut in, or a solid timber board covered with hessian or coir for grip. 

How this helps!

These materials block direct contact with frozen paving and stop heat loss through the base, while still allowing any excess water to drain away. 

Don’t.

Avoid letting pots sit in puddles, but don’t leave them perched on bare feet either — cold air moving underneath can chill roots even faster.

Do.

Wrap large pots with hessian, fleece, or bubble-wrap for extra side insulation and group pots together for shared protection.