Words by Most houseplants sold in stores come from tropical and subtropical regions, where days are long and humidity is high. Winter in a heated home is the opposite: little daylight, dry air and sudden temperature swings. Many plants slow their growth in response, and owners who keep caring for them as in summer often do more harm than good.
A few adjustments make a big difference.
Rethink the light
Daylight drops sharply in winter, especially in northern latitudes, and the sun sits lower in the sky. A spot that was bright in June may be dim in December.
- Move plants closer to windows. South- and west-facing windows offer the most light in the Northern Hemisphere. East-facing windows give gentler morning sun.
- Clean windows and leaves. Dust reduces the light leaves can absorb. Wipe broad leaves gently with a damp cloth.
- Rotate pots. Turning plants a quarter turn every week or two helps them grow evenly rather than leaning toward the glass.
- Consider grow lights. Full-spectrum LED grow lights are affordable and efficient. Set them on a timer for 10 to 12 hours a day for plants that need bright light.
Water less, but check more
Overwatering is the most common cause of winter houseplant deaths. When growth slows, plants use less water, and soil stays wet longer, which can lead to root rot.
- Check the soil before watering. For most foliage plants, wait until the top inch or two feels dry. Succulents and cacti should dry out almost completely.
- Water thoroughly, then drain. When you do water, let excess run out of the drainage holes, and empty saucers so roots don’t sit in water.
- Use room-temperature water. Cold tap water can shock roots.
- Watch for signs of trouble. Yellowing lower leaves, soggy soil and a musty smell suggest overwatering. Crispy edges and drooping in dry soil suggest underwatering.
Add humidity
Indoor heating can drop relative humidity well below 30 percent, while many tropical plants prefer 40 to 60 percent. Ferns, calatheas and orchids are especially sensitive.
- Group plants together. Plants release moisture, raising humidity around one another.
- Use pebble trays. Set pots on trays of pebbles with water below the base of the pot.
- Run a humidifier. This is the most effective option and benefits people, too.
- Skip frequent misting. It raises humidity only briefly and can encourage leaf diseases on some plants.
Protect from temperature swings
Most common houseplants are comfortable between about 60 and 75 degrees Fahrenheit. Problems arise at the extremes.
- Avoid cold drafts. Keep plants away from exterior doors and drafty windows, and don’t let leaves touch cold glass at night.
- Avoid heat sources. Radiators, heating vents and fireplaces dry plants quickly.
- Mind the move. When bringing outdoor plants inside for winter, inspect for pests and quarantine them for a couple of weeks before placing them with other plants.
Hold the fertilizer
Most houseplants don’t need fertilizer in winter, since they aren’t actively growing. Feeding a resting plant can lead to salt buildup in the soil and damage roots. Resume feeding in spring when new growth appears. Plants actively growing under grow lights, or winter bloomers such as Christmas cactus, may be exceptions.
Watch for pests
Dry, warm indoor air favors spider mites, and fungus gnats thrive in soil kept too wet. Inspect leaves, including their undersides, when you water. Treat early with a strong spray of water, insecticidal soap or neem oil, and let soil dry more between waterings to discourage gnats.
Save repotting for spring
Winter is generally the wrong time to repot. Disturbed roots recover slowly when growth is sluggish. Unless a plant is severely root-bound or has root rot, wait until spring.
Plants that cope well
If you’re shopping for easy winter companions, snake plants, ZZ plants, pothos and cast-iron plants tolerate low light and dry air better than most. Christmas cactus and amaryllis bring color during the darkest months.
With lighter watering, better light and a little humidity, most plants will come through winter ready to grow. For more ideas for your home, visit our Home section.