Humidity is how much water vapour the air holds. Leaves lose water into the air all the time, and the drier the air, the faster they lose it. Many popular houseplants come from humid forests, where the air is much moister than a typical home. Nebraska Extension notes that 30 to 50 percent relative humidity is the range recommended for people, that many homes are drier than that, and that many plants do best at around 70 to 80 percent.
Where you live changes the picture. Outdoors in Malaysia and much of tropical Southeast Asia, the air is humid most of the year, so a shaded balcony already suits many forest plants. Indoors is different: an air conditioner works partly as a dehumidifier, pulling water out of the air as it cools, so a plant next to the unit can sit in noticeably dry, moving air. In temperate homes, winter heating does the same.
The typical sign of air that is too dry for a plant is brown, crispy leaf tips and edges. Ferns, calatheas, marantas and rex begonias show it quickly. Tougher plants, such as cacti and succulents, pothos, philodendrons, dracaenas and cast-iron plant, cope with ordinary indoor air.
Key points
- Dry air makes leaves lose water faster.
- Air conditioning and heating both dry indoor air.
- Brown, crispy tips and edges on ferns and calatheas often mean the air is too dry.
Try this
Check where each humidity-loving plant sits. Move any that are in the direct airflow of an air conditioner, fan or heater a little further away.
Check yourself
Read more in the reference
Sources
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