Plants suffer from the winter blues too. The main culprit is the lack of humidity. When the heat comes on in the office buildings, the humidity all but disappears. You can relate to this… dry skin and eyes, the feeling of fatigue from the stale air.
Indoor office plants are tropical. They are native to places like Florida, Hawaii, and the Caribbean where it is humid year round. We try to fool nature by keeping them indoors, but living in a downtown office tower through a Canadian winter is about as far from tropical as it gets.
Light too is an issue. The daylight hours are significantly less. Indoor office plants are already receiving much less light than they do in their natural environment. Take away a few more hours a day and they become stressed. Don’t be surprised if they drop some leaves. This is a normal reaction to lower light levels; a plant can only support so many leaves. The plant will drop some as a survival reaction.
Stressed plants are more prone to infestation by a few common tropical plant pests such as spider mites, mealy bugs and scale. Spider mites are almost invisible to the naked eye. You usually see the gray webs along the edge of the leaves. The plant looks dry and has brown leaves, but the soil feels wet. Scale insect can be seen as small brown bumps on the underside of the leaves and along the leaf petiole (the part joining the leaf to the plant stem). Mealy bug looks like white cotton on the leaves.
What can you do to help the plants survive through the winter?
Most importantly, give your plants more water…considerably more. Most of the water you give it will end up in the atmosphere, absorbed by the dry air. Monitor it carefully for insects. If you see any, wipe the leaves thoroughly with a damp cloth and a bit of dish detergent, removing any visible insects. Routine cleaning will prevent the insects from multiplying as quickly. There are sprays available, but their effectiveness is questionable.
Consider purchasing a humidifier. You and the plants will benefit. You can mist the plants occasionally, but the humidity doesn’t last long and this is often not practical in an office environment. Additional lighting may help too.
Once the days start to get longer, and you notice some new growth on the plants, start fertilizing monthly. Continue this through until late fall.