Gadenin日本語Get the appIt is a winter grower, so it wants a cold room
The florist cyclamen grows and flowers through the cold half of the year and rests through the hot half. Everything about it is built for that. It makes its leaves and buds at temperatures a person finds slightly too cold for a sitting room, and it reads sustained warmth as a signal that its growing season is over. A plant kept at 70F (21C) will keep flowering for a couple of weeks on the buds it already had, then yellow off and stop, and no amount of feeding or repotting brings it back while the room stays warm.
The working range is roughly 50 to 60F (10 to 16C) by day and down to about 45F (7C) at night. Below freezing it is damaged, so it is not a plant to leave against a single glazed window on a hard frost night, but everything between frost and about 64F (18C) suits it. If you can see your breath in the room in the morning, the cyclamen is happy there.
The practical consequence is that the best places in a house are the ones nobody heats: a porch, an unheated spare bedroom, a landing window, a stairwell, a north facing kitchen windowsill away from the cooker, a conservatory that stays frost free. Plants sold in flower in autumn and taken straight to a warm living room are the ones that are finished by midwinter.
| Position | Suits a cyclamen? | Why |
|---|---|---|
| Unheated porch or entry hall with a window | Best | Cold, bright, good air movement, no radiator |
| North or east facing windowsill in a cool room | Very good | Even light without heat build up behind the glass |
| Cool bedroom or landing window | Good | Usually 10 to 15F cooler than the main living room |
| Living room shelf away from a window | Poor | Warm and too dim; buds abort and stems stretch |
| Directly above a radiator | Worst | Dry rising heat cooks the crown and collapses the leaves |
| South window in full midday sun | Poor | Leaf edges scorch and the pot heats through |
Light: as bright as you can give it, short of direct midday sun
Cold and dark is not the answer either. In the shortest weeks of the year a cyclamen needs all the light it can get to keep opening buds, so a windowsill rather than a table is the right place. Bright indirect light for most of the day, with an hour or two of low winter sun, produces short stiff flower stems and dense leaves. Direct summer strength sun through glass scorches the leaf margins and heats the compost, but winter sun through a north or east window is rarely strong enough to do harm.
A plant short of light tells you clearly. The flower stems stretch and flop outward instead of standing above the leaves, new buds stall at half an inch and never open, and the leaf stalks lengthen so the whole plant loosens and opens out from the center. That is not a watering fault and it does not correct itself in place. Move it to a brighter window and the next flush of stems comes up short and upright, though the stretched ones stay stretched.
Turn the pot a quarter turn every few days. Cyclamen lean towards a light source faster than most flowering pot plants, and a plant that has grown to one side through a whole winter cannot be straightened afterwards.
Glass is cold at night and hot by day. If the leaves touch a single glazed pane on a frosty night they can be blackened along the contact line, so pull the pot two or three inches (5 to 8 cm) back from the glass after dark or draw the curtain on the room side of the plant, not between the plant and the window.
Air, and why dry heat is the real enemy
The two things a cyclamen cannot tolerate are dry rising heat and stagnant, saturated air around the crown. A radiator or a heat vent below the plant supplies the first: the leaves go limp within hours, the flower buds dry and fail to open, and people read the limpness as thirst and water it, which sets up the second problem. Move the plant off the heat rather than watering it more.
At the same time the crown needs air moving over it. Cyclamen packed shoulder to shoulder on a shelf, or a plant left in the plastic sleeve it came home in, hold damp air among the leaf stalks and that is where gray mold starts. Give each plant a hand's width of clear space and take any decorative wrap off the pot the day you get it.
You do not need to mist it, and misting is actively counterproductive because it puts water into the crown. If the room is genuinely dry, stand the pot on a tray of damp gravel with the pot base clear of the water, or simply move the plant to a cooler room, which raises the relative humidity without any equipment.
Moving it through the year, and what to note down
The plant changes position twice a year. Through autumn, winter and early spring it is on the coolest bright windowsill you have. Once it begins to yellow off in spring it stops needing light at all, and the pot moves to a dry, shaded, airy place for the summer rest, where it stays until you restart it in late summer. Putting a resting pot back on a sunny sill and continuing to water it is the single most common way a cyclamen is lost in its second year.
Keep a simple note of where each plant stood and how it performed: the room, the window aspect, the coldest reading you saw there, the date the last flower opened. After two seasons the record tells you which windowsill in your house is actually the cyclamen sill, and that is worth more than any general advice, because houses differ far more than plants do.
Also note the date the pot went out to summer rest and where you put it. Resting tubers are invisible and easy to lose behind other things in a shed, and a pot found again in midwinter with a shriveled tuber in it is a plant that was never watered back into growth at the right time.