By January the air inside an old farmhouse gets as dry as a cracker, and my houseplants tell me so. Leaf tips turn brown and crispy, lower leaves yellow and drop, and a plant that looked fine in October starts to sulk. The cause is usually not neglect. It is dry heated air, weaker light, and the habit of watering on the same schedule as in summer.
Here is how I care for my plants from late fall until spring: how much to water, how to raise the humidity without special equipment, where to place the pots, and what to do about the most common winter troubles.
Why Winter Is Hard on Houseplants
Most houseplants come from warm, humid places, and an indoor summer with the windows open suits them well enough. Winter changes three things at once.
- Dry air. Heating removes moisture from the air, and leaves lose water faster into dry air than into damp air.
- Weak light. Days are short and the sun sits low, so most plants slow down or rest and use much less water.
- Uneven temperature. Cold spots form near windows, while radiators and heating vents blow hot, dry air.
Knowing this changes how you care for them. A resting plant needs less water, no fertilizer, and steady surroundings. It does not need rescuing every time one leaf turns yellow.
Water Less, but Do Not Stop
The most common winter mistake I see is watering by the calendar. In summer a pot may dry out in a week. In winter the same pot can stay damp for two or three weeks, because the plant drinks less and the soil dries more slowly. Keep watering on the summer schedule and the roots begin to rot. If you are not sure what that looks like, read about the signs of overwatering houseplants.
Check the soil, not the date.
- Push a finger into the soil up to the second knuckle, about two inches.
- For most leafy plants, water only when the top inch or two feels dry. Snake plants, ZZ plants and succulents like to dry out almost completely.
- Use room-temperature water, so the roots do not get a cold shock. A filled watering can left standing overnight is ready by morning.
- Water slowly until some runs out of the bottom, then empty the saucer after about fifteen minutes.
- Skip fertilizer from late fall until you see new growth in spring.
Do not stop watering altogether. A pot that dries out completely and shrinks away from its sides is as stressed as a soggy one. Lift the pot now and then: a light pot is dry, and a heavy pot still holds water.
Raise the Humidity Around Your Plants
Ferns, calatheas and peace lilies suffer most from dry air. Succulents, cacti and snake plants cope well and need no help. Three simple methods work in an ordinary house.
Group the plants
Leaves release water vapor, so a cluster of pots makes a slightly more humid pocket than one plant standing alone. Leave a little space between the leaves so air can still move.
Use a pebble tray
Fill a shallow tray with pebbles, add water until it sits just below the top of the stones, and set the pot on the pebbles. The pot must stand on the stones and not in the water, or the soil will soak up water from below and the roots stay wet. The effect is small and reaches only the air close to the plant, but it costs almost nothing. Refill the tray as the water evaporates.
Run a humidifier
If you keep many tropical plants, a small room humidifier does more than trays can. Clean it as the maker directs so it does not spread mold, and set it where children and pets cannot knock it over.
I do not rely on misting. A spray wets the leaves for a few minutes and then the effect is gone, and on fuzzy leaves, such as African violets, standing water can leave spots.
Move Plants Away From Heat and Drafts
Where a pot stands matters as much as how you water it. Walk through your rooms and look for these trouble spots.
- Radiators, heating vents and woodstoves. Hot, dry air scorches leaf edges. Keep plants a couple of feet away, or move them to a shelf off to the side.
- Cold window glass. On a freezing night, a leaf touching the pane can be damaged. Pull the pot back a few inches, or slide a sheet of cardboard between the plant and the glass.
- Outside doors. Each opening sends in a gust of cold air, which tropical plants dislike.
Most houseplants like what we like, a steady temperature between about 60 and 75°F. Sudden swings bother them more than a cool room does.
Light is the other change. A plant that did well in a dim corner in summer may need to move closer to the glass in winter, and wiping dust from the leaves with a damp cloth helps them use what little light there is. For tough plants that manage in dim rooms, see my list of easy houseplants for a north-facing window.
Winter Problems and What to Do
Brown, crispy leaf tips
This is nearly always dry air. Raise the humidity as above. You can trim the brown tips with clean scissors, following the natural shape of the leaf. They will not turn green again, but new leaves will be fine.
Yellow lower leaves
An occasional old leaf turning yellow is normal. Several at once usually means too much water in a cool, dim room, so let the soil dry further before the next watering.
Fine webs and speckled leaves
Spider mites enjoy warm, dry rooms. Wipe the leaves, rinse the plant in the shower with lukewarm water, and check it weekly.
Leaf drop after a move
Plants often drop a few leaves when they change places. Give the plant two weeks in its new spot before you change anything else.
Quick-Fire FAQ
How often should I water houseplants in winter?
There is no fixed number. Check the soil with your finger, since many plants need water only every couple of weeks or even less, depending on the plant, pot and room.
Should I mist my houseplants in winter?
Misting helps for only a few minutes. Grouping the plants, a pebble tray or a humidifier works better.
Do I need to fertilize houseplants in winter?
No. Most plants rest, and fertilizer salts build up in the soil. Begin again when new growth appears in spring.
Is it safe to keep houseplants near a radiator?
Not close. Hot, dry air burns the leaf edges and dries the soil quickly. Keep a gap of a couple of feet.
— Grandma Gigi
