Identium
Why Everything Is Dying in January (and What to Change Now)
Nothing changed about how you look after them. That is exactly the problem.
Everything looked fine in October. By late January the collection is yellowing, dropping leaves, covered in webbing, or dead.
Five things change at once in a heated house in winter, and they compound. Here they are in the order they actually kill plants.
1. You are still watering like it is summer
This is the biggest one by a distance.
Light halves, then halves again. The plant slows almost to a stop. Water use collapses. A pot that dried in five days in July can take three weeks in January.
Keep the summer rhythm and the soil never dries. Roots suffocate, rot sets in, and the plant wilts, which reads as thirst, so it gets watered again.
Fix: check the soil two inches down before every single watering. If it is damp, walk away. Most foliage plants want water every two to three weeks now, and snake plants, ZZ plants and succulents can go six weeks or more.
2. The air is drier than a desert
Central heating routinely drops indoor humidity to 20 or 30 percent. For comparison, tropical foliage plants evolved somewhere nearer 60 to 80.
You see it as brown crispy tips and edges, curling, and new leaves that fail to unfurl properly.
Fix: group plants together so they share transpired moisture, stand pots on trays of damp pebbles with the pot base clear of the water, or run a humidifier in the room with the fussiest plants. Misting does almost nothing and leaves water sitting on leaves overnight.
3. Spider mites are having their best month
Warm and dry is exactly what spider mites want. In those conditions a generation completes in five to seven days, which is why an infestation seems to appear from nowhere in February.
Fix: hold white paper under a leaf and tap it. If specks fall and then walk, you have mites. Treat weekly for three weeks and raise the humidity, which genuinely suppresses them.
4. There is not enough light, and the plant has stopped pretending
Winter light is weaker, lower and there is much less of it. A spot that was fine in June can be below what a plant needs in December, and it responds by shedding leaves it cannot afford to run.
Fix: move everything one to two feet closer to the window, but not touching cold glass. Clean the leaves and clean the windows, since both cut an already small supply. A cheap grow light on a timer changes what is possible in a genuinely dark flat.
5. It is sitting in a hot or cold draught
Radiators, heating vents, draughty doors, single glazed windows. Many plants get both a hot updraft and a cold draught across a single day.
Fix: get plants off radiator shelves and out of the path of vents. Leave a gap between foliage and cold glass overnight.
What to do in what order
- Stop watering on a schedule. Check the soil every time, water only when dry at depth. Nothing else matters as much.First
- Stop feeding entirely until spring growth appears. A plant that is not growing cannot use it, and the salts build up.First
- Move everything closer to the light, clean leaves and windows.This week
- Check leaf undersides for mites and scale on every plant.This week
- Move plants away from radiators, vents and cold glass.This week
- Deal with humidity for the tropicals only. Ferns, calathea, maranta, alocasia. Ignore it for succulents and snake plants.Then
- Do not repot until spring unless you find root rot.Wait
What is normal and does not need fixing
Losing a few of the oldest lowest leaves. Growth stopping entirely for months. Christmas cactus looking spent after flowering. Succulents doing absolutely nothing.
What is not normal: rapid loss of many leaves at once, mushy stems, wilting while the soil is damp, or fine webbing. Those are problems.
The one framing that helps
Your plants are not in decline because they are weak. Their conditions changed completely in October and their care did not. Almost everything on this list is a case of doing in January exactly what was correct in July.
If you are not sure which of your plants actually want the humidity treatment and which want to be left bone dry until March, the answer is species specific and the difference is large. Photograph a leaf with the stem visible and Identium will tell you which regime each one is on.
Frequently asked questions
Why do houseplants die in winter?
Usually because watering did not change when the conditions did. Light halves, growth stops and water use collapses, so a summer watering schedule keeps the soil permanently wet and the roots suffocate. Dry heated air, less light, spider mites and draughts from radiators compound it.
How often should I water houseplants in winter?
Check the soil two inches down before every watering rather than following a schedule. Most foliage plants need water every two to three weeks in winter against weekly in summer, and succulents, snake plants and ZZ plants can go six weeks or more.
Should I move plants closer to the window in winter?
Yes, by one to two feet, but not touching cold glass. Winter light is weaker and lower, so a position that was adequate in June can be below what the plant needs in December. Cleaning the leaves and the windows also recovers a surprising amount of an already reduced supply.
Why do spider mites appear in winter?
Because warm dry indoor air is close to ideal for them. In those conditions a generation completes in five to seven days, so a population that was invisible in November is severe by February. Raising humidity suppresses them, which is one of the few pest problems where changing the environment does real work.
Is it normal for plants to lose leaves in winter?
Losing a few of the oldest, lowest leaves is normal as the plant sheds what reduced light will not support. Rapid loss of many leaves at once, mushy stems, wilting while the soil is damp, or fine webbing are not normal and point at overwatering, cold damage or pests.