Winter care comes down to four changes. Move plants closer to the light. Water less. Add humidity for the plants that need it. Keep leaves off cold glass and away from heat vents.
I grow houseplants in Armstrong, British Columbia. Winter here means short days, dry furnace air, and windows cold enough to hurt a leaf. Most plant advice is written for milder places. This is what works in a real winter.
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What winter does to a houseplant
| Change | What it does | What you see |
|---|---|---|
| Short days and low sun | Less light, so the plant makes less food | Slow or no growth, pale new leaves, leaning |
| Furnace heat | Dries the air | Brown, crispy tips and edges |
| Cold windows and drafts | Chills leaves and roots | Black or see-through patches, sudden leaf drop |
| Slow growth | The plant drinks less | Soil stays wet, yellow leaves, fungus gnats |
A plant that stops growing in winter is not sick. It is resting. The goal is to hold it steady until spring.
Light: move everything closer
Light is the biggest winter problem this far north. In December the days are short and the sun is weak.
- Move plants toward the glass. A plant that sat a meter (3 ft) back in summer can sit beside the window in winter.
- Use your south and west windows. Winter sun is gentle. Plants that would scorch in a south window in July are fine there in January. Move them back in March, when the sun gets strong again.
- Wash the windows. Clean glass lets in more light. Wipe the dust off leaves too.
- Turn the pots. A quarter turn at each watering keeps plants from leaning.
- Add a grow light. A full-spectrum bulb on a timer for 10 to 12 hours a day carries succulents, variegated plants, and anything that is fading. Amazon carries full-spectrum LED grow bulbs that fit a standard lamp. Read how to choose a grow light for houseplants.
Water: less, and by touch
More houseplants die from winter watering than from winter cold. A resting plant in low light uses little water. Soil that dried in a week in July can take three weeks in January.
Stop watering on a schedule. Push a finger into the soil and water only when it is dry to the depth in the plant’s guide. Use room temperature water, since cold tap water shocks the roots.
Read how often to water houseplants in winter for the full method, and how to tell if a houseplant is overwatered or underwatered if a plant looks unwell.
One exception. A plant on a shelf above a heat vent or next to a wood stove can dry out faster in winter than in summer. Check those pots more often, or move them.
Humidity: the furnace problem
Winters in Armstrong are dry. My whole-house humidifier cannot keep up, and I struggle to hold 35% humidity. That is hard on my instruments and on my plants.
My calathea crisps up. My Norfolk Island pine does not handle furnace air well at all. It can dry to a crisp.
Here is what helps.
- Put a hygrometer next to your fussiest plant. Know the number before you fix it. A small digital hygrometer from Amazon does the job.
- Run a humidifier in one room. Gather the plants that need it there, and keep the door closed.
- Move plants away from vents, baseboard heaters, and stoves. A meter (3 ft) is the minimum.
- Group plants together. It helps a little, and it is free.
- Skip misting. It lasts minutes.
Read how to increase humidity for houseplants in winter for which fixes work.
Plants that do not care about dry air make winter easier. Snake plant, ZZ plant, hoya, jade plant, aloe vera, and ponytail palm all handle furnace air.
Temperature: cold glass and drafts
Most tropical houseplants want to stay above 15°C (60°F). Damage starts for many of them below 10°C (50°F).
A room can read 20°C (68°F) on the thermostat while the air beside a window is far colder. On the coldest nights the glass itself can be near freezing.
- Keep leaves off the glass. A leaf that touches a cold window turns black or glassy. Leave a gap of a few centimeters.
- Do not trap plants behind curtains. The space between a closed curtain and the window gets as cold as the glass. Pull plants into the room before you close the curtains at night.
- Check for drafts. Doors that open to the outside, mail slots, and old window frames all leak cold air. Move tropical plants away from them.
- Lift pots off cold floors. A tile or concrete floor chills the roots. A plant stand or a piece of cork under the pot helps.
- Avoid hot spots too. The top of a radiator and the mantel above a fireplace cook plants.
Feeding, repotting, and pruning: wait
- Stop fertilizing from about October to March. A plant that is not growing cannot use it, and the salts build up in the soil.
- Do not repot unless a plant is in trouble. Roots are slow to heal in winter. Wait for spring, then follow how to repot a houseplant step by step.
- Prune only dead or broken parts. Save the shaping for spring.
Plants under a grow light for 12 hours a day are the exception. They keep growing, so they can take a light feeding.
Winter pests
Dry, warm, still air is good for pests.
Spider mites. They love furnace heat. Look for fine webbing and pale speckles on the leaves of palms, calathea, alocasia, and English ivy. Rinse the leaves in the shower and raise the humidity.
Fungus gnats. Small black flies around the pot mean the soil stays too wet. Read how to get rid of fungus gnats in houseplants.
Mealybugs and scale. Check leaf joints and the undersides of leaves once a month. Wipe them off with a cotton swab dipped in rubbing alcohol.
What is normal in winter
Do not panic over these.
- No new leaves for two or three months.
- A few old, lower leaves that yellow and drop.
- A weeping fig that sheds after a move.
- Alocasia, caladium, and purple shamrock that die back and rest.
- Smaller, paler leaves on anything that does keep growing.
Yellow leaves all over, mushy stems, and wet soil are not normal. Read why houseplant leaves turn yellow.
Buying plants in winter
A tropical plant can be damaged in the walk from the store to the car.
- Ask the store to wrap the plant, pot and all, in paper or a bag.
- Warm up the car first.
- Make the plant shop your last stop, and take it straight inside.
- Do not have plants shipped in a cold snap unless the seller adds a heat pack.
Winter bloomers earn their keep
Winter is when holiday plants do their work. A Christmas cactus blooms in the darkest weeks. An amaryllis goes from bulb to flower in a few weeks on a sunny sill. When my amaryllis rests, it rests in the dark. A closet or a cool basement is fine.
A poinsettia can live long past the holidays. I have kept them going. It needs proper light to do it.
A month-by-month plan
| Month | What to do |
|---|---|
| October | Bring summer plants inside. Stop feeding. Move plants closer to windows. |
| November | Set up the humidifier and hygrometer. Cut back on water. Check for pests. |
| December | Keep leaves off cold glass. Wrap any plant you buy for the trip home. |
| January | Water by touch only. Wash windows and dust leaves. Watch for spider mites. |
| February | Days get longer. Look for the first new growth. Hold off on feeding. |
| March | Move plants back from south windows as the sun gets stronger. Start feeding at half strength. Plan spring repotting. |
If your plants spent the summer outside, read how to bring houseplants inside for winter without bugs.
Quick answers
How cold is too cold for houseplants? Most tropical plants get damaged below 10°C (50°F). Keep them above 15°C (60°F) to be safe.
How often do I water houseplants in winter? Less often than in summer. Check the soil with a finger and water only when it is dry.
Do houseplants need fertilizer in winter? No, unless they are growing under a grow light.
Why are my plant’s leaves falling off in winter? Low light, a cold draft, or wet soil. Check all three.
Can I repot in winter? Wait for spring unless the plant has root rot.