By mid-October the frame is already earning its keep. On frosty mornings the glass runs with condensation an hour before the house is warm, and the seedlings inside look almost smug about it.
This issue we keep a month-long diary of one cold frame on a north-facing allotment: what went in, what came up, and what the frost taught us about patience.
The frame is a small piece of architecture, and like all good architecture it keeps its promises quietly. Lift the lid at dawn and the air inside smells of damp soil and green growth; close it before dusk and the day's warmth is banked for the night.