PlantHumidity.
The amount of water vapour in the air; relative humidity (RH) expresses it as a percentage of the maximum the air can hold at that temperature.
What it means for your plants
Heated indoor air in winter often falls to 20–35% RH; most common houseplants cope at 40–60%, and thin-leaved ferns and calatheas prefer 50–70%. A clean humidifier is the only reliable way to raise room humidity, since misting lasts minutes.
IN PRACTICE
A digital hygrometer next to a calathea reads 28% RH in January and 55% once a humidifier runs nearby.
Put it into practice
Heated homes often drop to 20–35% humidity in winter. Learn which houseplants really need more, why misting and pebble trays barely help, and how to run a humidifier.
Houseplant humidity: what actually raises it, and what doesn’t
