As temperatures drop outside, our houseplants transition from outdoors to inside for overwintering. In doing so, they must adjust to seasonal changes as well as shifts in their immediate growing environment. Even our full-time houseplants have to adapt to varying temperatures and indoor conditions.

While lighting, watering, and temperature are key cultural conditions for houseplants, humidity plays a close role in health and vigor. Many of our favorite specimens are native to tropical and subtropical climates, including rainforests, where moisture is prevalent.

While the average relative humidity in our homes is often enough to support their growth, winter brings drying conditions that lower available air moisture. Whether staying inside for the cold season or as long-term residents, there are steps we can take to boost humidity for houseplants in winter.

Dry Winter Air and Houseplants

It depends on the species, but many houseplants do well with a relative humidity of around 50-60%which is average in our homes. In winter, cold air holds less humidity. Indoors, we run vents, heaters, and fireplaces, drying the surrounding air. Lower humidity all around means it may drop below the cultural threshold for our houseplant collection.

Plants draw moisture up from the roots through their stems and leaves, releasing it from tiny pores on the leaf surface. Water loss happens faster when humidity is low, or in direct sun, high temperatures, or drafts. In winter, leaves may show brown and crisp edges and tipsan indication that they can’t keep up with moisture loss from transpiration due to low humidity or drafty conditions.

The first measure to maintain humidity around houseplants in winter is to avoid placing pots near a heat source (radiators, fireplaces, central heating vents). Keep them away from cold blasts near open doors, which can be drying but more so damaging due to sudden temperature fluctuations.

Humidity Tricks

It’s tempting to mist leaves and stemsbut this only raises humidity around houseplants in winter for a short burst of time, evaporating in even a few minutes. It can also increase disease issues from damp conditions.

Unless the plant is one that benefitsmisting isn’t a reliable way to boost relative humidity for long periods. Here are some reliable ways to increase humidity for houseplants in winter.

Bring in a Humidifier

A humidifier is the most reliable way to boost humidity for houseplants in winter consistently. In dry winter air, the rise in moisture helps houseplants and humans, too.

Place a portable humidifier near the plants, especially in large rooms, so they’ll benefit from the immediate moisture. It may run for several hours a day to be effective, and one with a monitor and timer can help ease use.

For arid or particularly dry environments, a humidifier installed in the HVAC system can help maintain average air moisture.

Group Plants

Like birds of a feather, houseplants with similar humidity requirements go together. Cluster tropicals so they benefit from transpiration and evaporation from their neighboring specimens and soil moisture. Increasing the immediate humidity with natural plant processes helps sustain the group.

Grouping pots is especially helpful in small spaces where humidity stays close. It’s worth trying in larger spaces, too, either on its own or combined with other humidity-raising measures. The more pots, the better when it comes to a grouping.

Craft a Pebble Tray

A tray of pebbles and water adds a bit of moisture to dry winter air. Use a two to three-inch deep dishtwo to three inches wider than the pot, and place the pot so that it sits near the tray. Make sure the container doesn’t sit in the water to avoid excess moisture absorption and problems like root rot.

As the water evaporates from the tray, it may increase moisture around foliage. Fill the saucer as needed, and clean it every week or so to avoid mold and mildew. Use the pebble tray method in cooperation with other tricks, like grouping houseplants for a little microclimate.

Move Them to a Humid Room

A room that holds more moisture, like the kitchen or a bathroomis a good fit for a single houseplant or group of houseplants. Moisture levels vary by the size of the space, frequency of water use, air flow, and other factors, but they set a good stage as opposed to rooms with a lack of moisture.

Even with higher humidity, the rooms must receive sufficient light exposure to support photosynthesis and specific growing requirements.

Employ a Cloche

To protect individual humidity-loving specimens against dry winter air, a simple glass or plastic cloche forms a mini-greenhouse. A plastic container, like a clear two-liter bottle, becomes an insulating cover. It captures moisture from transpiration and soil to increase ambient humidity.

A terrarium or an aquarium retains moisture in the same way. Allow air circulation and reduce excess moisture buildup by removing the cover on occasion. Letting in airflow and allowing moisture to escape helps reduce fungal problems from damp conditions.

Additional Winter Care

As with boosting humidity for houseplants in winter conditions, adjusting the watering regimen is essential to houseplant health. As temperatures cool and growth naturally slows, plants take up less moisture. Water evaporates less quickly from the soil (unless in high heat or dry, drafty air).

Water based on soil dryness rather than a weekly schedule, using a touch test to gauge water needs. It depends on the species, but dry soil to a depth of an inch or two usually indicates it’s time to water.