Winter: keeping tropicals alive in a heated home
In winter the radiators drop humidity to 30% and the light halves. The season when most plants are lost: how to walk them into rest instead of forcing them to grow.
Winter is the season when most plants are lost, and almost never to cold itself: they are lost to the side effects of the heating and of the light going away. Understanding what changes in the house from November to February, and adjusting, is half the craft of keeping tropicals indoors.
What actually changes
First, humidity collapses: radiators take household air from 50% down towards 30%, a desert for an understorey plant. Second, light halves and more — short days, low sun, often overcast: a spot that was bright in summer is half-dark in winter. Third, many tropicals, sensing the drop in light, naturally slow their growth: that is not illness, it is rest.
The most important practical consequence: if the plant slows down, you slow down too. Less water, because a plant that is not growing and transpires little dries its substrate far more slowly — keeping the summer rhythm means holding the roots in the wet and rotting them. Less fertiliser, or none: feeding a stalled plant only builds up salts. The finger in the substrate, in winter, will tell you to wait far more often than you expect.
With humidity, though, you have to do the opposite: put in more effort exactly as the air dries out. It is the season when a humidifier or a cabinet makes the difference between a plant that gets by and one that opens twisted, dry leaves. Grouping the plants away from the radiators helps a good deal.
Beware the wrong spots, which turn into traps in winter. On or near a radiator: scorching, bone-dry air, the leaves fry. On a sill against cold glass at night: a leaf touching the glass can freeze, and in any case takes sharp swings between day and night. In a draught — by a door that opens onto the cold, or under a leaky window: tropicals hate cold moving air more than still cold. The right winter spot is bright, away from radiators and draughts, off the freezing glass.
On light, if the summer position is no longer enough, moving the plant closer to the window is the first step; if that is not enough, an LED bar for the dark months settles it. This is not fanaticism: for many species, through a northern Italian winter, it is simply what gets them to spring in shape rather than stretched and threadbare.
The underlying idea: in winter you do not push, you accompany. Do not expect new leaves, do not force growth with water and fertiliser. The aim of the cold season is not to grow the plant — it is to carry it alive and healthy through to March, when the light comes back and it starts again on its own.