As fall gradually transitions to winter, we bundle up against the crisp air while soaking up every last minute of daylight. In a similar fashion, indoor plants make seasonal adjustments too.
During the darker winter months (roughly October through February in the PNW), it’s best to let plants “rest” after producing growth all spring and summer, allowing them to go into a period of dormancy. Indoor plants also tend to struggle during winter months due to various factors, including changes in available light, cold drafts, hot/dry air, and relocation for holiday decorations (Christmas tree, etc.). Therefore, houseplant care in fall and winter involves a few changes. Below are some of our best tips to keep your indoor plants thriving in the fall and winter.
While winter in the Pacific Northwest adds to the beauty of the seasons, shorter days and frequent grey skies mean less sunlight. So, during this time, plants will benefit from any light available.
- By moving houseplants closer to a window during winter months (south-facing windows are usually brightest), it offers ample light to keep them comfortable during dormancy. Most cacti and succulents need ample light to maintain bright colors and compact form.
- If space or natural light is limited, supplementing with indoor grow lights allows plants to maintain adequate UV light absorption. Miracle LED bulbs or elegant Soltech Aspect pendant lights set to 12–13 hours per day can help plants thrive during winter. These lights are available at the plant shops in our garden centers.
- Rotate plants regularly to encourage balanced growth.
Watering amounts and frequency should always be tailored to individual plant needs and may vary based on growing conditions such as light exposure. Less sunlight means less photosynthesis—the process by which plants use sunlight to convert energy from carbon dioxide and water. Therefore, in winter when sunlight is scarce, houseplants do not need as much water:
- Plants that receive weekly water can transition to every 2–3 weeks, or can simply be watered when the soil is almost completely dry.
- Cacti and succulents that are watered 1–2 times per month during the growing season do best with benign neglect—cactus plants can often go untouched through the majority of winter. Look for signs like slight wrinkling or puckered foliage to indicate dryness.
- Use room temperature water when watering plants during winter.
- Make sure plants do not sit in wet drainage saucers.
- Try bottom watering by setting the plant in a basin of water for several minutes until it has absorbed water from the holes in the bottom of the pot.
Air & Humidity
As we cozy up inside, the use of fireplaces, wood stoves, and other heating sources can dry out houseplant soil. Make sure your plants are not in front of vents or kept too close to draughty doors or cold windows. For plants like Ficus, it’s important to maintain a consistent air temperature to avoid leaves dropping. For humidity-loving plants, there are several ways you can raise humidity levels indoors to compensate for dry air:
- Humidifiers: use larger ones for entire rooms or smaller tabletop ones to target certain plants
- Misting: use a fine mister consistently each morning so water can evaporate throughout the day (can encourage foliage diseases if not done carefully)
- Grouping plants together: plants can help boost one another’s humidity (Ikea display cases)
- Wet pebble trays: fill a tray with 1–2 inches of pebbles and water to the top of the pebbles; place plants on top to enhance humidity
- Domes/Cloches: place over the plant; remove for a bit each day so the plant can “catch its breath”; not recommended for certain plants—lack of circulation can cause fungal diseases
During spring and summer, fertilizer encourages plants to convert more energy and grow. In contrast, fertilization is not recommended during winter months, as plants do not require additional nutrients through rest periods (most plants use stored energy during winter) and can even be damaged (foliage burn) by overfertilization when dormant.
- The exception to this is a gentle, organic fertilizer such as Joyful Dirt—due to its organic properties and mycorrhizae base, plants are not at risk of being burnt.
- Compost tea or worm tea can be used to help increase the soil microbe population or worm castings can be applied as a thin top dressing but should be covered lightly with a layer of potting soil to promote water absorption.
Repotting is not recommended during the dormant season. It may not seem like it to you, but repotting can be a big deal from a plant’s perspective… moving is hard! It can often lead to overwatering, fungus gnats, root rot, or other problems if done during winter. Even if you think you should repot now, you can probably wait another 6 weeks! It is best to wait until the active growth cycle (spring and summer) before repotting. Here are some things you can do in the meantime to keep your houseplants thriving:
- If potting soil is old and crusty, break it up lightly with a chopstick or plastic fork.
- Remove the top layer of old soil (up to 1 inch) and replace it with fresh potting soil or a thin layer of worm castings covered with a thin layer of potting soil.
- Provide aeration by making vertical holes in the soil with a pencil/chopstick (lightly insert about halfway into the root ball and make 4–6 small holes); be cautious of damaging large roots.
- Decorative pots are best used as “cache pots”—plants are placed in a plastic, draining container which is then set into the decorative pot (not planted directly into the decorative pot).
- Avoid plant propagation during winter as well, and don’t expect to see much growth on plant cuttings or divisions.
Monitoring & Troubleshooting
Give your houseplants regular checkups. Keep a consistent schedule, like weekly or bi-weekly, to thoroughly inspect plants (with good lighting) for signs of pests or problems.
- Wipe dust off the foliage with a soft cloth. Take notice of any unusual spots, bumps, or discoloration; use a magnifying lens to help identify potential pests.
- Trim off damaged or discolored foliage (take note of the location to help diagnose reason); it’s often best to cut the entire stem and leaf off rather than only the damaged portion of a leaf.
- Use neem oil on a soft cloth to thoroughly wipe tops and bottoms of “problem plants” once per month. Check product on small section before using on entire plant; some foliage types can discolor from contact with neem oil. “Problem plants” are those that have common struggles with spider mites or other known pests (spider mites love palms, cast iron plants, citrus, crotons; mealy bugs love pothos, dieffenbachia, cacti, hoyas; scale love ficus, palms, dracaena, citrus)
- Only water if and when necessary; it’s better to allow plants to go slightly too dry than constantly keep them wet.
- Learn to live with a little bit of imperfection!
Treat problems promptly!
- Isolate plants with pest problems to avoid further spread.
- Consider a 1–2 week quarantine for newly purchased plants to keep your other plants healthy.
- Ask for help from your local garden center—take photos or place leaf samples in a closed bag.
- Keep a basic plant care tool kit: magnifying lens, chopsticks, cotton swabs, soft cloth, small paintbrush or makeup brush, rubbing alcohol, neem oil, insecticidal soap, mosquito bits (fungus gnat control), plastic sheeting, garbage bags or drop cloth, spray bottle
So, let’s all get cozy and relax as we spend more time indoors. It’s been a hard year and our plants have really been there for us—they deserve their rest.