Winter Care for Houseplants

Houseplants, like their human caretakers, need a little more TLC this time of year, during the darker, shorter, drier days of winter. They rely on us to keep them strong during a season that is anything but forgiving. There are helpful winter-care tips I've come across that I thought I'd share with houseplant lovers out there.

I recently acquired two beautiful Autumn Ferns (Dryopteris erythrosora) that are keeping my dining room looking lush. 

There are four primary factors to monitor for happy, healthy houseplants: water, soil, light and temperature. During the winter months, these factors become even more important to consider. Here's a look at each of these factors with some basic winter care instructions.

WATER:

Every houseplant is different. Different species require different water levels and different levels of humidity to thrive. Finding out what species of houseplant you have and how much water it requires for a healthy existence is crucial; a little research goes a long way. As a general rule, however, plants actually require less water during the winter months because they are in a natural dormant stage. They are not expending as much energy to grow or reproduce.

The drier indoor air during the winter months does tend to sap moisture from your rooms. Dry soil surface, however, is not a good indication that your plant is thirsty. A good trick is to insert your baby finger into the soil of the plant at least an inch below the soil surface. If the soil is dry at this level, the plant can use a drink.

Moisture loving plants, like ferns, may need watering a little more consistently than others, but succulents and cacti will likely need no watering at all until spring. Signs of under-watering include dry, brittle leaves and wilting stems. Signs of over-watering include yellowing tips on the leaves, soggy soil and wilting.

Humidity: 

Houseplants generally like a 50% humidity level; in the winter, indoor rooms can be as low as 10%.

Misting your plants won't help much during the winter. The air is so dry that most of the mist will evaporate before the plant has time to absorb the moisture through its leaves. To help improve moisture levels for houseplant care, consider using a humidifier in the home. You can also stand the houseplants on a large tray of water filled with pebbles. The water will evaporate around the plants, keeping their immediate atmosphere moist. Continue to refill the water as it evaporates. Just ensure the plants are not standing directly in the water as this may cause root rot.

Another good tip is to cluster your plants together. Since plants naturally release water through their leaves, the plants will share the emitted moisture and create a supportive mini-ecosystem!

SOIL:

Your plants will be just fine without any plant food or fertilizer for the winter months. They are naturally resting and may resent the added injection of energy that comes with supplements. Hold off until early spring.

LIGHT:

The shorter days of winter can be detrimental to light-loving plants. The increase in cloud cover also doesn't help. You may need to move your plants closer to the windows or relocate your plants to a brighter spot in the home during the winter. A south- or west-facing window would be ideal. Even plants that do not need much light to survive will appreciate improved lighting during the winter. If windows are few and far between, you could invest in a grow-light but be sure to read the instructions before using it.

TEMPERATURE:

Most plants thrive between 60 and 75 degrees Farenheit -- rarely any lower than 50 degrees or higher than 85 degrees. Adjust your thermostat accordingly and keep plants away from cold drafts (entryways) or heat sources, such as radiators and fireplaces.

References: 

These books, above, are considered the bibles of houseplant care. Both were written by botanist and professional gardener Peter McHoy.

My own sources are my grandmother's old copy of Better Homes and Gardens special issue, "Favorite Houseplants" from 1977 and the New York Times "Book of Houseplants", published in 1973.