Whether you’re new to owning houseplants or have an ever-expanding collection, ensuring your plants are hydrated is one of your main responsibilities. Paying attention to the moisture in the soil is important.

During the colder months, indoor plants typically receive less sunlight, which means their growth slows down. Slower growth typically means houseplants need less water. “When light quantity and duration decreases, photosynthesis and certain other biological processes slow down, explains Leslie F. Halleck, certified professional horticulturist based in Dallas, Texas, and author of Gardening Under Lights.

However, there are factors, such as light levels, home temperature, and humidity, that will influence how much water your plants need.

• Leslie F. Halleck is a certified professional horticulturist based in Dallas, Texas, and author of Gardening Under Lights.
• Lisa Madz is the resident plant expert for Rosy Soil.

Less Light Means Slower Growth

In winter, days are shorter and there’s less natural light, affecting plant growth. “Houseplants typically need less water in winter, because they experience slower growth and reduced transpiration due to lower light levels and cooler temperatures,” says Lisa Madz, resident plant expert for Rosy Soil. The rate of photosynthesis slows down and the amount of water houseplants can absorb is reduced.

However, most houseplants don’t go dormant like many outdoor plants but they will have a slower growth period. “Plants may experience what we call quiescence, or a slower quiet period,” says Halleck.

Know Your Home, Region, and Plants

The weather outside may be cold or even freezing but the indoor temperature and humidity level are what is key to knowing your houseplants’ needs in winter. There isn’t a one-size-fits-all answer to watering your houseplants in winter since your geographical region and the warmth of your home are important factors.

“Where you live, your climate, local weather, and your HVAC system influence light, temperature, and humidity. That determines much and how often you need to water your plants seasonally,” says Halleck. “Everyone’s environment and light availability varies greatly, as do the needs of different plant species.”

Running the heater will keep you warm and cozy but it does dry out the air.  “If you’re running heaters, your indoor air is likely bone dry, which means it can hold more water vapor,” says Halleck. “Humidity inside the home can drop by 10-15% in the winter months, meaning that your plants may lose more water faster via evapotranspiration and evaporation of moisture from the growing media,” she says. “So even though there is less light available, more water is leaving your plant.”

When Houseplants May Need Less Water in Winter

There are situations where you may need to water less in winter, such as in higher humidity regions or if your plants are near a window. “If you live in a climate with higher natural humidity and cool temperatures, you’re running humidifiers for your plants, or your plant sits next to a cold glass window, then you very well may need to reduce your watering in winter,” she says. One way to create more humidity in your home is to have several houseplants placed near each other. “Grouping plants together can create a more humid microenvironment, benefiting them in drier indoor winter conditions,” says Madz.

When Houseplants Need More Water in Winter

Because most people are running heaters in their homes in winter, it’s possible that your houseplants may dry out faster, meaning they may actually need more water than at other times of the year. “My houseplants wilt far more often in winter than they do in summer when I’m cooling the air with air conditioners,” she says. “Air conditioners also remove moisture from the air, but the cooler air temperatures reduce transpiration.”

Knowing how much to water your houseplants is not always obvious or straightforward with so many variables and nuances. If you want to ensure healthy and thriving plants, Madz recommends, “Adjust the watering frequency based on the specific needs of each plant and the environmental conditions.”