Temperature for House Plants

Almost all house plants come from tropical and subtropical climates with temperatures very much like those in our homes. A daytime temperature range of anywhere from 65° to 75°F (18° to 24°C) is just perfect for them, and most plants have no trouble tolerating occasional summertime highs of up to 90°F (32°C).

Generally speaking, indoor temperatures that you find acceptable will also be just fine for healthy growth of your house plants.

geraniums
These geraniums grow well in the indoor temperatures of most homes.

Controlling Temperature for House Plants

Even tropical plants like cooler air at night than during the day. As a result, healthier growth will be seen if temperatures drop 5° to 10°F (3° to 5°C) at night. Night temperatures naturally drop indoors, especially near windows, but you can also turn the thermostat down at night to accentuate the change. Such cooler night temperatures are not only good for house plants and humans, they also help conserve energy.

Long periods of extreme heat can be harmful to house plants. You can increase ventilation through screened windows or a fan. Air conditioning will also help bring temperatures down to acceptable levels, but house plants should not be put directly in the path of cold drafts. Since humidity is removed from the air through air conditioning, some means of increasing humidity may be necessary, especially in dry climates.

Some Like It Cool

Subtropical plants, especially those forced into winter bloom in cool greenhouses, are not as tolerant of warm temperatures as most indoor plants. They can be placed near a cool window in winter or in a room that is only slightly heated. You can also make a mini-greenhouse by bending two clothes hangers into a half circle and attaching them to the window frame, then covering the hangers with a sheet of plastic. Temperatures inside the mini-greenhouse will often be up to 10°F (5°C) cooler than the surrounding air.

In the next section, we'll talk about fertilizing house plants.

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