Temperatures to Bring in Potted Plants

If you put your potted houseplants out on your deck or porch for the summer, bring them inside before outdoor nighttime temperatures drop to the point where the plants will suffer damage from cold. Many of our most popular potted houseplants originated in warm climates and can be damaged by cool nights even if temperatures still are well above freezing.

...
Potted houseplants need to be taken indoors before overnight temperatures dip below 45 degrees Fahrenheit.

45 Degrees Critical

Early September is the time to move houseplants back indoors, said the University of Vermont Agricultural Extension Department's website. Houseplants need to be taken indoors before overnight temperatures dip below 45 degrees Fahrenheit. Most tropical plants suffer harm from temperatures below 40 degrees. If the plant is crowding the pot, repot it into a larger container before taking it indoors.

Making the Transition

Before moving your plants indoors, check them for insects and diseases and treat as appropriate. Plants can suffer shock from the sharp differences between outdoor and indoor conditions unless you take care, said the University of Vermont website. If your plants have been in bright outdoor sunlight, put them in a south-facing window or under a grow light. Some leaves may droop and fall off, but the plant will replace these as it adapts to the lower light level.

Less Watering

When moving potted plants back indoors, wait to water them until the soil is dry to the touch. Don't water them on cloudy or rainy days as the plant won't get sufficient light and air to dry out. Finally, said the University of Vermont website, give your plants a dose of fertilizer according to product directions.