Cold Damage: how to recognise and treat it

Growing conditions

Symptoms

Right after a frost, leaves look water-soaked and dark green, then turn brown or black; stems of tender plants may collapse.
Tender young growth is scorched, with pale brown patches between the leaf veins, mostly on the exposed top and edges of the plant.
Frost-damaged blossom turns brown and few or no fruits form; young fruits may get a corky layer.
After several days of cold but above-freezing weather, warm-season crops such as peppers and tomatoes are stunted, wilt or have puckered leaves.

Once no more frost is expected, prune out damaged growth, cutting back to an undamaged sideshoot or bud.
Do not give up on a damaged plant too soon; many regrow from buds at or below soil level, sometimes not until early summer.
When more frost is forecast, cover plants overnight with a double layer of fleece or an old sheet.

Reference information, not a guarantee. Read and follow the label of any product: dose, safety and the days to wait before harvest.

Watch the forecast; if the soil is dry, water it well in advance of a frost — moist soil stores more daytime heat and releases it at night.
Move containers to shelter or a greenhouse, and lift tender perennials such as dahlias before the first frosts.
Mulch the root area of tender plants with a thick layer of organic matter so the ground does not freeze.
Harden off tender plants and plant them out only after the danger of frost has passed; avoid nitrogen-rich feeds late in the season.

Figures checked against these sources.