Plant care
Trim Greenhoodtemperature & humidity
Pterostylis concinna
More about trim greenhood
Ideal temperature for trim greenhood
Aim for 4-22°C (39-72°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 4°C growth pauses; cold beyond that pushes it into dormancy rather than killing it outright.
Cold tolerance & winter care
Trim Greenhood is comparatively hardy (USDA 8-10 (cool greenhouse or outdoor in mild temperate zones), RHS H4). 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 trim greenhood
Trim Greenhood sits happiest at around 45-65% relative humidity. Moderate humidity is appropriate, matching the temperate coastal habitats of this species. Avoid very dry, heated rooms in winter when the plant is actively growing. Good air movement is important. 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.
Trim Greenhood temperature & humidity — frequently asked questions
What temperature is best for trim greenhood?
Trim Greenhood grows best between 4-22°C (39-72°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 trim greenhood tolerate?
Trim Greenhood starts to suffer below roughly 4°C. It tolerates a cold dormant period within USDA 8-10 (cool greenhouse or outdoor in mild temperate zones), but a wet cold root zone is more dangerous than cold air.
What humidity does trim greenhood need?
Trim Greenhood prefers about 45-65% relative humidity. Moderate humidity is appropriate, matching the temperate coastal habitats of this species. Avoid very dry, heated rooms in winter when the plant is actively growing. Good air movement is important.
How do I raise humidity for trim greenhood?
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 trim greenhood live outside?
Trim Greenhood is rated for USDA zone 8-10 (cool greenhouse or outdoor in mild temperate zones) and RHS hardiness H4. 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 trim greenhood care
In the UK? Keeping trim greenhood warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full trim greenhood care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.