Just because houseplants live indoors in a controlled environment for most — if not all — of the year doesn’t mean their needs don’t change with the seasons.
“To hardcore hobbyists, gardeners and horticulturalists, we refer to any season that’s not the growing season as the dormant season,” says Chris Satch, plant doctor for plant subscription service Horti. “It’s simply a season with less-than-favorable conditions.”
The dead of winter doesn’t have to mean dead plants, though.
We spoke with Satch and other plant experts to find out how to care for houseplants during the colder months. Here are their suggestions.
Transition outdoor plants in
Some houseplants thrive outdoors during spring and summer, especially in high-humidity areas, but they will struggle during winter. If they’re in pots and you can bring them inside, then Eileen Zedd, owner of the Wild & Home Plant Shop in California, recommends doing so as early as possible, when the overnight temperatures start dropping to between 50 and 55 degrees. Julie Czeck, a green goods buyer for Terrain, adds that, for subtropical plants, which includes many houseplants, “if it reaches too close to 40 degrees Fahrenheit, many of them will turn to mush.” Cut back dead leaves or branches when you bring the plants inside, so they can focus their energy on living leaves and new growth.
Check for pests
Before bringing any outdoor plants inside, make sure they are pest-free. Otherwise, all of your indoor plants will be infested before long. If you notice signs of pests — including spider mites, mealybugs and scale — then Brittanii Jackson, of Air By Michelle in Washington, D.C., says to isolate the plant and use a mixture of 1 teaspoon of vinegar per gallon of water to wipe down the leaves. Spray neem oil a few days later to prevent further pests. If it’s a plant with many (or intricate) leaves, she says, “shower your plants” in the bathroom. Jackson also says that, when you buy a new plant, you should “always keep it isolated until you think it’s safe.”
Dust the leaves
“We don’t realize it, but plants collect dust,” Zedd says. “The dust prevents the leaves from taking in the nutrients from the light.” Because there’s already less light during winter, this chore is particularly important. As for tools, Zedd says, use whatever you have on hand: microfiber cloths with a spray of mild soap and water, baby wipes or a feather duster. “I sometimes sit mine in the bathtub and give them a good drink,” she adds.
Put them in light
Because many plants need more than five hours of direct sun a day and there’s less daylight in winter, Satch says to feel free to move your plants around. “The myth that plants hate to be moved is exactly that: a myth. Any plant is happy to move,” he says, “so long as the conditions in the new spot are better.” Position plants in the brightest part of your home, if only for a couple of hours a day.
“I get light in the morning in my bedroom and then in the afternoon closer to my patio,” Zedd says. “I’ll move my plants around, so they can get a couple of hours of sun.” If it’s hard to find natural light, Jackson recommends investing in grow lights.
Keep plants warm — but not too warm
Cold air from a door, window or other drafty spot will give plants a shock. “It’s important that your plant leaves aren’t hitting the windows,” because the glass is cold, Jackson says. “No open windows, no drafts coming through.” At the same time, keep plants away from direct sources of heat, such as vents, running heaters or fireplaces, so they don’t get hot and dry out. “You don’t want them too hot or too cold,” Zedd says. Most houseplants will do well between 60 and 70 degrees.
If the air around the plant is cooler, it’s going to take in less water, because there’s less heat and light to help move water through the plant and evaporate it out of the leaves. “So you want to reduce the watering,” Zedd says. “When I talk to people who are new to plants, I tell them to start watering once a week and adjust from there. That’s a good rule of thumb for the wintertime, too.” However, she says, pay more attention to the plant than the schedule. Look to see whether the leaves are getting yellow, brown or crispy, which means they need more water. Likewise, if you put your finger in the first inch of soil and it’s damp, hold off on watering.
Don’t forget about humidity
Many indoor plants are tropical and prefer more humid air. Humidifiers are an option, but you can also buy — or make — a less expensive and more decorative humidity tray. Put water in a tray filled with pebbles, then set the plant on the rocks. The moisture will evaporate up and around the plant, giving it more humidity than the rest of the room. Some plant experts recommend spray bottles, but Satch says to only use them with orchids, air plants and bromeliads; other plants prefer taking water up through the roots.
Set aside fertilizing
“A lot of plants go dormant during the winter,” Zedd says, “so we don’t need to fertilize them. Less light equals less water equals less growth.”
Jackson agrees: “Fertilizing is very important in the summer and spring months, but not winter.”
Hold off on repotting
Try to wait to repot — which stimulates growth — until spring, when the plant wants to be growing, Czeck says. “If you really need to repot something during the winter, it’s probably not going to kill your plant,” though it’s not ideal and may cause stress. March or April can be a good time for repotting, depending on your climate.