Although they live indoors, houseplants “know” what season it is by the length of daylight and the angle of the sun. Winter days can be short and dark, and when the sun does appear, it is low and in the southern portion of the sky. Similar to the plants outside, indoor plants slow their growth and go somewhat “dormant” for winter from October through February or early March.
Frequently, indoor plants struggle during winter months due to various factors:
- Changes in available light
- Cold drafts from windows or frequently used doors
- Hot/dry air from furnace vents, heaters, or fireplaces
- Relocation for holiday reasons (Christmas tree, etc.)
We have compiled a list of winter houseplant “Do’s and Don’ts” to help you and your plants thrive this season.
- Water less frequently. Decrease watering to almost half and make sure plants do not sit in wet drainage saucers—water only when plants show signs of being dry with room-temperature water.
- Increase humidity by using a pebble tray or humidifier, or by misting plants twice daily (especially beneficial for ferns and Calathea).
- Rotate plants regularly to encourage balanced growth.
- Inspect plants weekly and dust/clean off leaves with neem oil, gentle shower spray, or water and a soft cloth.
- Avoid cold drafts from windows or frequently used doors
- Keep clear of heater vents, fireplaces, or wood stoves—place diverter on floor vent if possible.
- Re-pot from October through February: Dormant, tropical plants will be slow to adjust to their new environment which could lead to overwatering problems such as fungus gnats or root rot. If soil is compacted and hard, use a pencil or chopstick to gently aerate by making several vertical holes, and try watering from the bottom by setting plant in a basin of water for several minutes until it has absorbed water from the holes in the bottom of the pot.
- Fertilize right now: Most plants photosynthesize so efficiently that they are using up stored energy during winter; added nutrients are unnecessary and may cause a brown or black tip “burn” on foliage as the excess fertilizer is processed. A very diluted, organic liquid or gentle product like Joyful Dirt may be used when necessary. 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.
- Expect to see much growth on plant cuttings or divisions: Avoid doing much indoor plant propagation during winter. Trimming off dead or yellowing leaves is okay and should be expected, as some plants reallocate nutrients from lower leaves to areas higher up on the plant resulting in color changes and occasional leaf-drop.
Seasonal/Holiday Plant Care & Selection
Poinsettias are a classic way to transform a space into a festive wonderland or say “Merry Christmas” with a living gift. The most popular flowering indoor plant sold in the U.S., poinsettias are native to Mexico and are available in red, white, burgundy, pink, and even multicolored varieties.
- Light: Bright, indirect light; no direct sun. Avoid letting leaves touch cold window glass.
- Water: Best kept evenly moist, but not wet. Allow top 50% of the soil to dry before watering. Do not allow plant to sit in water—if plant feels heavy, wait several days until it feels lighter before watering. Remove plastic/foil wrap and avoid getting the leaves wet, which can cause spotting.
- Fertilizer: Not necessary when poinsettia is flowering.
- Temperature: Very sensitive to cold; do not put outside. Ideal indoor temp is 65–70° F during the day and around 60° F at night. Keep away from drafty doors/windows, fireplaces, heaters, etc.
- Pests/Diseases: Avoid overwatering to prevent disease. Monitor for pests such as whiteflies, fungus gnats, mealy bugs and spider mites.
- Flowering: The most colorful part of a poinsettia are the leaves, which turn shades of red or develop dramatic patterns as the plant blooms. The actual flowers are tiny yellow buds in the center that slowly open over time. For longest display time, select plants with mostly closed flower buds.
- Toxicity: Mildly poisonous; may cause vomiting or drooling in pets/children if ingested. Milky, white sap is very bitter and can cause redness, itching, or irritation on skin. “Kalsettias” are seasonal arrangements of flowering kalanchoes and poinsettias. Kalanchoes are very toxic to pets; avoid if you have a pet that may be tempted to sample them!
Also a common holiday plant, Christmas cactus are easy to care for and can live for 100 years! They produce tubular flowers in white, pink, red, yellow, salmon, and fuchsia. Not actually true cacti, these plants are epyphites and are part of the Zygocactus group, joined by Thanksgiving and Easter cactus, each blooming around their namesake holiday.
- Light: Bright, indirect light; no direct sun. Medium/low light is okay, but may cause flower buds to drop off or even prevent them from blooming.
- Water: Allow top 50% of the soil to dry before watering; reduce watering after blooms fade. Buds will fall off if too dry, and root rot is caused by overwatering.
- Fertilizer: Provide ½ strength, liquid, all-purpose food in spring and summer, about twice monthly; stop feeding after September. Plants love leftover tea as well.
- Temperature: To set flower buds, plants need cool daytime temps of 60–65° F and 45–55° F at night. Once buds have developed, they prefer warmer temps of 65–70° F.
- Flowering: Occurs when days are short and cool; begins early fall.
- Pests/Diseases: Watch for mealy bugs and scale. Avoid overwatering to prevent bacterial root rot.
- Soil & Pot Size: Rich, acidic, well-draining soil. Keep slightly root-bound for best flowering. Only repot in spring, never during bloom.
- Toxicity: Christmas cactus are non-poisonous.
Other Holiday Plants
- Bulbs: Paperwhites & Amaryllis
- Hellebores, Rosemary, etc.