Frost Damage
Risk near you, next 48h
See whether your local forecast favours this disease right now.
When it strikes
Fix the cause, not the leaf
No spray will help here. The trigger is soil, water supply, nutrition or temperature, so change the growing condition and judge the result on new growth, not on damaged leaves.
Not contagious
Nothing spreads from plant to plant here. Neighbouring plants showing the same signs are reacting to the same soil, water or weather, so fix the cause rather than isolating plants.
Safe to compost
No pathogen carries over on this material, so it can go on an ordinary heap with the rest of the garden waste.
When and where to look
Scout the planting once temperatures drop below 2°C. Risk builds after roughly 2 unbroken hours of those conditions, so the morning after such a night is the moment to look.
The signs that lead here
Full problem lists for these crops
About
Frost damage happens when ice forms inside plant tissue and ruptures the cell walls. A late spring frost on soft new growth and open blossom does far more harm than a much colder night in midwinter, because dormant tissue is genuinely frost-hardy and new growth is not.
Symptoms
Leaves and shoot tips blacken, go limp and hang down, then dry to brown paper within a few days. Blossom turns brown at the centre and sets no fruit. Split bark and dieback on woody plants may not appear until weeks later.
Organic Treatment
Do not cut anything back until growth restarts — the damaged tissue shelters the buds behind it, and it is impossible to judge what is truly dead for two or three weeks. Water the roots, which are usually untouched, and shade plants from early morning sun, since rapid thawing does more damage than the freeze.
Chemical Treatment
Nothing chemical helps. Avoid feeding damaged plants with nitrogen, which forces more soft growth into a season that may bring another frost.
Prevention
Watch the forecast rather than the calendar, and keep fleece to hand from bud burst until the last frost date has passed. Avoid planting tender crops in frost pockets at the bottom of a slope, never plant out early to gain a fortnight, and water the soil the evening before a frost — moist soil releases more stored heat overnight.
Crops at risk
Related problems
Frost Damage risk by location
Each location has a month-by-month profile computed from the weather archive: how many hours a year actually meet this disease’s thresholds.