Light levels are different in winter. So the amount of light shining through an east-facing window will be less in winter than in summer. Then too, there are fewer hours of daylight in winter and, in many parts of the country, there's less sunshine in general -- because of snow, rain, or general cloudiness.
All of this affects houseplants. Many need more light than they're receiving. How can you tell? Here are some signs to look for:
* Leaves cup upward. (This is particularly true for African violets.)
* The plant is obviously growing more toward the light. (You notice the extra growth in one direction when you give the plants their weekly quarter-turn.)
* New growth differs from previous growth -- leaves are smaller and maybe not as green; stems elongate and the plant gets leggy.
* Falling leaves.
What can you do about it? The simplest solution is to move the plants to a spot with more light. Nearer a window will help. Or move the plant to a west-facing window if it's in an east window or from a north window to an east one. (If plants have become leggy, pinch them back after moving.)
You may also want to consider removing any barriers to light reaching your plants -- sheer curtains, for instance. This one's a little tricky because, as you know, some plants don't like direct sun at all.
I think I've mentioned this before, but it bears repeating -- dust on houseplant foliage lessens the amount of light the plant receives/uses. Deb Brown of the University of Minnesota suggesting removing the dust by wiping the stems and leaves with a soft, damp cloth.
But for me, the easiest way to clean indoor plants is to cart them to your shower and give them a short, gentle rain of water. Then leave them in the shower till they dry off. This also has humidifying benefits, so plants really like it.
Reflected light -- from a mirror or aluminum foil -- can help if there's enough sun to reflect. (And rooms with white walls reflect more sun than those with dark walls.)
An alternative is artificial lighting. Shop lights from the hardware store or somewhere like Home Depot work well for cuttings and small plants you can group together.
No, you don't need expensive grow lights because you aren't trying to get houseplants to grow in the winter. What you want is to give them enough light to meet their winter needs. Molly Day suggests i one 40-watt cool bulb plus one 40-watt warm bulb in a fluorescent fixture.
But there is an appearance drawback to shop lights -- you really wouldn't want them in the living room.
Individual plant lights (often called spot lights) are a good choice for large plants that may be difficult to move to a spot with brighter light, or that you simply don't want to move. They can be attractive, although pricey.
Something new -- and appealing -- is LED grow lights, which use much less energy than traditional kinds and have a very long life. I haven't tried them yet, but you can read about them here, here, and here.
Do keep an eye on your houseplants in January and February, to see if they're telling you they need more light. By March, things will be returning more to normal and you can begin returning them to their places in your home.
And if you're in the market for some new houseplants, consider those that don't mind low light.
(NOTE: To go to the Monitor's main gardening page -- which contains articles and blog posts on many topics -- click here.)