Houseplants in the Winter
By Rob Sproule
“Say aloe to my little friend.”
Less Light = Less Water:
Feeling sluggish? Light levels plummet in the winter leading to precious little Vitamin D to energize us. We feel tired, a little cranky, and pass the comfort food. Your plant relies on sunlight for its metabolism even more than we do. As light levels fall, expect its growth to slow. Leaves may fall and its immune system will weaken, making it more vulnerable to opportunistic pests. Increased humidity will help it fight them off (see below).
Water less. How much less depends on the plant. Some slow down, some go downright dormant. In the summer you’ll have gotten used to watering when the soil surface is dry. Kick that habit. The dry air will parch the surface but underneath the sleepy roots will be drowning in dampness. Stick your finger in and only water if it’s dry up the first knuckle.
The vast majority of houseplants, with the glaring exception of succulents and cacti, hail from tropical regions where the air is saturated with water and thrive in the near 100% humidity. In our stark Prairie winter the plants go from an acceptable 50% household humidity to a parching 10-20%.
With the air literally pulling moisture from our plants’ pores, it’s hard to imagine how a Ficus or Bird of Paradise can survive. But there are tricks:
– If you don’t have a good humidifier in your furnace, consider investing in a smaller one. It will benefit your health as much as the plants.
– Cluster your house plants close together so they can benefit from the moisture their neighbours are losing. Tropical plants don’t like being alone in any season.
– If your bathroom and/or kitchen is well lit, lug some of plants in there for the winter so they benefit from the running water and steam.
– Put a bed of stones in your plant’s saucer and fill with water. The plant should sit just above the water but will benefit from the water evaporating just below it.
As for misting: it doesn’t hurt, but it’s not enough on its own. The water sits on the leaves for such a short time that there’s no time for it to absorb in before it evaporates.
Beware the Draft:
In the frozen North, we’re used to annual temperature swings of up to 80 degrees from one extreme to the other. In the tropics, a swing of just 10 degrees can be a big deal. So as much as you need to beware the cold in winter, beware the heat, too.
If your plant is near a door, especially a big swinging front door that’s often used, back it up. A few -20 blasts could be fatal. Likewise, if it’s near a heat vent, oven, or fireplace, the desiccating air will add to the havoc the already dry winter air is playing.
If your trops are close to (ie. leaves touching) old windows, consider pulling them back a scootch. If the glass freezes it will kill the touching leaf and send shivering shockwaves through the plant.