The University of Maryland Extension: Temperature and Humidity for Indoor Plants says most indoor air is too dry, especially in winter, and that all plants except cacti and succulents benefit from higher humidity. It lists a pebble tray, grouping plants and an automatic humidifier, and calls the effect of misting questionable. The RHS guides read for this site disagree on misting: it says to mist stephanotis freely, but to avoid misting gardenias in flower.
What works, according to the sources
| Method | What Maryland Extension says |
|---|---|
| Pebble tray | Set pots on a tray of pebbles and water |
| Grouping | Clustering plants raises humidity around them |
| Humidifier | An automatic humidifier can help plants and people |
| Misting | Questionable whether it raises humidity; if you mist, use tepid water, skip fuzzy-leaved plants, and mist early so leaves dry before evening |
Where the RHS differs
The RHS gardenia guide says gardenias need high humidity, to stand pots on damp gravel and to avoid misting while plants are in flower. The RHS hoya guide says hoyas dislike dry air during the growing season and to stand the pot on damp gravel or clay pellets, keeping the water just below the surface. For stephanotis, the RHS houseplant notes say to water and mist freely while growing. So for scented plants, damp gravel appears most often, and misting advice depends on the plant.
Temperature and drafts
Maryland says foliage plants like 70 to 80°F by day and 60 to 68°F at night, flowering plants the same by day but 55 to 60°F at night, with nights 10 to 15°F lower than days. It says flowering varieties are sensitive to drafts or heat from registers, so keep plants away from heating and cooling sources.
What the sources do not cover
The Maryland page gives no humidity percentages, and neither source says how much a pebble tray raises humidity. Humidity and bud drop are discussed in Low Humidity Bud Drop and Gardenia Humidity Indoors.
Frequently asked questions
Does misting raise humidity?
Maryland says it is questionable. The RHS advises against misting gardenias in flower.
Does a pebble tray help?
Maryland lists it as a method, and the RHS recommends damp gravel for gardenia and hoya. Neither gives a measured effect.
What is a good nighttime temperature for flowering plants?
Maryland says 55 to 60°F, with nights 10 to 15°F cooler than days.
Sources read for this page
- University of Maryland Extension: Temperature and Humidity for Indoor Plants
- RHS gardenia guide
- RHS hoya growing guide
Last reviewed 15 October 2026. Written by Md. Firozur Rahman. This page gives general guidance and cannot diagnose a plant from a description; see the Disclaimer.
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