Plants are super keen on seasonal changes, and have different needs in the winter as compared with the summer. In the winter, the sun is setting (much) earlier, swinging lower in the sky, and is often covered with clouds. Although your plants are inside, these changes will impact them.
Here are a few things to keep in mind:
Mind the drafts – A temperature flux or draft can seriously stress your plants out. Some plants are extra sensitive to drafts, and will immediately decline if it gets in the low 60’s (I’m looking at you, Tillandsia!) Keep your plants away from heating units, radiators, fires, and from open windows or front doors that might create drafts. Remember, if its chilly for you, it’s chilly for your plants!
Dormancy – In the winter, the days are short- so short that most tropical plants will enter a phase of dormancy from October to February. Because of this, it is important to tweak your watering schedule. Allow soil to dry out completely between waterings. This may mean waiting longer between waterings, or reducing the amount given (but try not to do both at once unless absolutely necessary). If you know your plant prefers humid conditions, like the Bird’s Nest Fern, mist it weekly so it stays moist but not soaked. Soaked soil can lead to root rot.
Put away the fertilizer – Give your plant a much deserved break.
Sunlight – If your plants are leaning towards their light source, gradually rotate them to help them straighten up. PROTIP: If your plants are spindly and reaching for the light, that means that they are not getting enough light.
Dust – Dust off leaves bi-weekly. Closed windows during the winter increases dust and indoor pollution. Dust and dirt build-up can reduce the amount of light getting to your plant – which can be detrimental when days are short! To combat extreme build-up, use water with a drop or two of lemon juice or household soap and a soft cloth.
Artificial lighting – Consider supplemental lighting. The secret sauce? It’s all in the bulb! You can use any fixture so long as it’s 1-3 feet from the plant that needs it. Although there are many lightbulbs on the market, how do you know which is good for you? Go for a bulb that has >850 lumens of output, ideally in white. Either CFL or LED will do, but plants tend to respond to CFL better (until LED tech gets better).
Winter travel – If you’re travelling, and you’re worried about the plants getting too dry, you can simply move them away from sources of heat including the window. Temporary light deficit while you’re gone will cause the plant to use less water. Find more vacation plant care tips here.
Some dieback is OK – With less light, plants will drop their leaves to compensate. If light is food for plants, less light means less food, which means that the plant can’t feed all of its leaves. Therefore it makes an executive decision to drop them. However, your plant may have grown to a summer size during the summer, and is now dying back, but not completely dying off. That is just the plant adjusting to the level of food that it is receiving. PROTIP: If you know (or sense) that your plant is overgrown, you can pull off a few leaves anywhere to force the plant to not drop any extra leaves. This is useful for keeping the plant fuller and bushier, as opposed to leggy.
If you keep your plants happy during the winter, they have a bonus effect – studies have shown indoor plants combat SAD (Seasonal-Affective Disorder). If you feel seasonal depression or seasonal moodiness, plants are proven to help reduce that stress and anxiety, and even bring happiness to offices, workspaces, and even homes!