Houseplant Care in January
January is the lowest-light month of the year in most of the US, and the most common month for houseplant deaths. The cause is almost always overwatering.
Cut watering frequency 30–50% from your summer schedule. Move plants closer to windows. Stop fertilizing. Watch for spider mites in dry, heated air.
Light in January
In most US latitudes, January delivers 9–10 hours of weak, low-angle sun. Even your south window now sits in what your plant’s biology reads as "medium" or "low" indirect light. Move sensitive species (calathea, fiddle leaf, anthurium) right up to the glass. Snake plants and ZZ that "tolerate low light" still grow more if you nudge them closer.
Watering in January
Slower growth + lower evaporation = much less water. Iowa State Extension documents that overwatering peaks in winter, not summer, because owners maintain their warm-month schedule. Cut frequency 30–50% and confirm dryness 1–2 inches into the soil before watering.
Pests and problems to watch in January
Heated indoor air drops humidity to 20–30% — prime spider mite territory per UC IPM. Inspect leaf undersides weekly. Also watch for fungus gnats from soil staying wet too long.
What to plan now
Now is the time to research grow lights before March repot season. Order seeds if you propagate. Most-loved houseplants on Amazon go on sale post-holidays.