Winter is when most indoor plants are lost. Not from cold (they live with you, at room temperature), but from invisible conditions that change drastically: dry air from the heating, half the daylight, cold drafts, pests. Here is how to make it through cleanly.

What changes in winter

Light: 50 to 70% less than summer depending on latitude.
Ambient humidity: drops to 25-30% with heating on (vs 50-60% the rest of the year).
Temperature: variable, with swings near windows.
Photoperiod: short days, slowed metabolism.

Result: the plant uses less water, does less photosynthesis, and pests thrive in the dry air.

The 7 winter rules

1. Halve the watering

The number one mistake. People keep watering at summer pace and drown their plants. In winter:

Green plants (Pothos, Monstera, Ficus): every 12-15 days instead of 7.
Snake plant, ZZ: every 4-5 weeks.
Cacti, succulents: every 30-45 days, sometimes none for two months.

Always check the substrate with a finger before watering.

2. Boost ambient humidity

Heating dries everything. Solutions, most to least effective:

Electric humidifier: $30-60, easily brings humidity back to 50%.
Group plants: they create their own microclimate.
Pebble tray with water: under the pot, slow evaporation.
Misting: useful for Calathea, ferns. Not for succulents.

3. Keep away from heat sources and cold windows

A plant on or next to a radiator dries out in days. The opposite, a plant pressed against a single-pane window can sit at 40°F overnight.

Ideal distance: 20 inches minimum from any heat or cold source.

4. Maximize available light

Clean the windows once in November, raises light by 15%.
Move plants closer to the brightest window.
Rotate the pot a quarter turn each week to balance phototropism.
For demanding species (orchids, variegated Calathea), consider a 20W LED grow light, plugged in 8 hours a day.

5. Stop fertilizing entirely

Fertilizer in winter = root burn. The plant is dormant, not absorbing. No fertilizer from October to February.

Gradual restart in March, half-dose for the first month.

6. Watch for pests

Dry air is paradise for spider mites and mealybugs. Inspect the underside of leaves every two weeks.

At the slightest fine web or white spot, treat immediately (lukewarm shower + diluted insecticidal soap). In winter, infestations spread faster because plants are weakened.

7. No repotting in winter

Unless emergency (root rot), wait for spring. Cut roots heal poorly in winter, and the rot risk is high.

Species that suffer the most

Species	Main issue	Priority fix
Calathea	Dry air	Humidifier essential
Ferns	Dry air	Move to bathroom
Ficus benjamina	Drafts	Do not move, keep away from windows
Peace lily	Lack of water	Substrate slightly moist
Orchids	No cool nights	Room at 60-63°F

Species that love winter

Christmas cactus: blooms in December if cool and short photoperiod.
Succulents: dormancy, often take on nice tints.
Cyclamen: the only houseplant that flowers in January-February.
Snake plant, ZZ: indifferent, they barely notice winter.

The winter calendar

October: last fertilizer, reduced waterings, set up the humidifier.

November: photoperiod at minimum, watch pests, wipe leaves.

December: maintenance only, no repotting, check humidity.

January: hardest period, maximum vigilance on watering.

February: first signs of recovery on some plants, just wait.

March: gradual return to watering, first half-dose fertilizer, first repotting if needed.

With Plenova

Plenova automatically adjusts reminders by season. You water less in winter, the app knows. You skip fertilizer, the app does not suggest it. All you have to do is observe your plants and enjoy the calm season.

Overwintering plants is just letting them rest the way they expect. April will be more generous because of it.