Houseplant Care in December
Water sparingly. No fertilizer. Check for pests regularly while the heat is running. Raise humidity where you can; most indoor plants grow best at 40 to 50%, per Iowa State Extension.
Light in December
The shortest days of the year. Plants far from windows need a grow light even if they tolerate low light: University of Missouri Extension notes that even low-light plants usually don’t get enough light more than 10 feet from an average window.
Watering in December
Plants need less frequent watering in winter (Iowa State Extension). Cacti and succulents need very little, and aroids need much less than they did in July. Check the soil before every watering.
Pests and problems to watch in December
Dry heated air favors spider mites (UC IPM), while most indoor plants grow best at 40 to 50% humidity (Iowa State Extension). Fungus gnats follow overwatering. Keep plants out of cold drafts, which Iowa State Extension lists among the causes of leaf drop, yellowing and browning.
What to plan now
Plan your repot list for March. Wishlist any species you want to add next spring. Read up on light meters before January’s short days.