Plant care
Curly Endive 'Frisee'temperature & humidity
Cichorium endivia var. crispum 'Frisee'
More about curly endive 'frisee'
Ideal temperature for curly endive 'frisee'
Aim for 10 to 22°C (50 to 72°F) on the thermostat and you've handled the easy part. The hard part is the half-metre around the plant: window glass that drops to near-freezing on a January night, a radiator pumping out hot dry air, a draught from an opened front door. Move the plant 30 cm and you've usually fixed the problem. Below roughly 10°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Curly Endive 'Frisee' is comparatively hardy (USDA Cool-season annual; tolerates light frost, RHS H3). Within that range it tolerates a cold dormant spell outdoors; outside it, grow it in a container you can move under cover or overwinter in a cool but frost-free spot. Hardiness assumes an established plant in well-drained soil — a wet, cold root zone kills far more plants than cold air alone.
Humidity for curly endive 'frisee'
Curly Endive 'Frisee' sits happiest at around Ambient outdoor relative humidity. An outdoor salad crop with no special humidity needs. Good spacing and airflow help keep the frizzy hearts dry and reduce grey mould in cool, damp weather. The usual low-humidity tell is crisp brown leaf tips and edges while the soil moisture is fine — a sign the air, not the watering, is the problem. If you need to raise it, the reliable methods are grouping plants together, standing the pot on a tray of damp pebbles (the pot above the waterline, never in it), or running a small humidifier in winter when indoor heating dries the air most. Misting is the least effective — it raises humidity for minutes, not hours.
Curly Endive 'Frisee' temperature & humidity — frequently asked questions
What temperature is best for curly endive 'frisee'?
Curly Endive 'Frisee' grows best between 10 to 22°C (50 to 72°F). Keep it out of cold draughts, off freezing windowsills in winter, and away from the hot dry air directly above radiators — the extremes matter far more than the average room temperature.
How cold can curly endive 'frisee' tolerate?
Curly Endive 'Frisee' starts to suffer below roughly 10°C. It tolerates a cold dormant period within USDA Cool-season annual; tolerates light frost, but a wet cold root zone is more dangerous than cold air.
What humidity does curly endive 'frisee' need?
Curly Endive 'Frisee' prefers about Ambient outdoor relative humidity. An outdoor salad crop with no special humidity needs. Good spacing and airflow help keep the frizzy hearts dry and reduce grey mould in cool, damp weather.
How do I raise humidity for curly endive 'frisee'?
Group it with other plants, stand the pot on a tray of damp pebbles (kept above the waterline), or run a small humidifier in winter. Misting only helps for a few minutes, so it is the weakest option for a plant that genuinely needs more humidity.
Can curly endive 'frisee' live outside?
Curly Endive 'Frisee' is rated for USDA zone Cool-season annual; tolerates light frost and RHS hardiness H3. Within that range it can stay outdoors; outside it, grow it in a moveable container and protect the roots from a wet, cold winter.
More curly endive 'frisee' care
In the UK? Keeping curly endive 'frisee' warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full curly endive 'frisee' care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.