How to Protect Plants From Frost
Priya Hollis · Oct 17, 2026 · 5 min read
Quick answer
A single cold night can undo a summer’s work. Know which plants are at risk and what actually keeps them safe.
Frost damage happens when water inside plant cells freezes and ruptures them. Tender plants blacken overnight; hardier ones may lose new growth or flower buds.
Most protection is cheap and simple, as long as you act before the cold arrives.
1 Know when frost is likely
Frost is most likely on clear, still nights, when heat radiates away from the ground with no cloud to hold it in. Low-lying areas and the bottom of slopes collect cold air and are often the first to freeze. Look up your area’s average first and last frost dates as a guide.
2 Plants most at risk
- ✓Tender perennials such as dahlias, cannas, and pelargoniums
- ✓Citrus, olives, and other potted Mediterranean plants
- ✓Young seedlings and newly planted vegetables in spring
- ✓Early blossom on fruit trees
3 Quick protection
- ✓Cover plants with horticultural fleece in the evening and remove it in the morning
- ✓Move pots against a house wall or into a greenhouse, shed, or porch
- ✓Water dry soil during the day — moist soil holds more heat
- ✓Avoid plastic touching leaves directly, since it transfers cold
4 Over winter
Lift dahlia tubers after the first frost blackens the foliage, or mulch them deeply in mild areas. Wrap large pots in bubble wrap or hessian to stop roots freezing, and raise them on pot feet so they drain. Bring tender plants indoors before the first forecast frost.
5 If plants do get caught
Do not cut back frosted growth straight away. The damaged leaves protect the growth beneath from further cold. Wait until the risk of frost has passed, then trim back to healthy tissue.
This is general gardening information. Results depend on your climate, soil, and conditions. Follow label directions for any fertiliser or treatment, and check whether plants are toxic to pets or children before bringing them home.