Cyclamen care: cool temperatures, tuber and dormancy

Light

Bright, indirect light is the consensus across the sources: Clemson, NC State, UF/IFAS and the RHS all ask for a well-lit spot out of direct sun. A cool east window is close to perfect, and a north window works in a bright room. Hot afternoon sun through glass warms the leaves past the range the plant tolerates and shortens flowering.

Too little light causes its own problems. Clemson explains that light levels in most homes are not high enough, which leads to long leaf stalks, smaller blooms and paler colors, and NC State says low light makes the plant weak. If yours is stretching, move it closer to the window rather than into a warmer room. When a resting tuber pushes new leaves in mid-September, Clemson moves it into a much brighter position to build a compact plant.

Water

The tuber is the weak point. Water that pools in the crown, where stalks meet the top of the tuber, rots it from the center out. NC State and Clemson both say to water along the edge of the pot or from below. The RHS method works well: stand the pot in a few centimeters of water for about five minutes, then lift it out and let it drain fully. Water again when the surface feels dry to the touch.

Keep the mix moist but never soggy while the plant is in leaf. A cyclamen in a warm room or near a heat vent dries out fast, and Clemson warns that a vent will dry the soil too quickly. The RHS adds a useful reassurance: occasional drying out is less harmful than overwatering. A plant that wilts from thirst usually revives after a soak, while a rotted tuber does not.

When the leaves begin to yellow after flowering, cut back. The RHS reduces watering as the plant goes dormant for summer, and NC State says watering should be reduced at that stage. Clemson adds a caution: do not let the mix dry out completely during dormancy. Resume regular watering once new leaves appear in early fall.

Soil and pH

NC State recommends a rich, well-drained soil, and any good houseplant mix with some perlite meets that standard. Drainage holes matter more than the exact recipe, because a cyclamen sitting in wet compost is one watering away from tuber rot. When new leaves appear after dormancy, the RHS replaces the top layer of compost with fresh peat-free mix rather than disturbing the tuber.

Humidity

NC State recommends moderate humidity, so ordinary room air is enough as long as the plant is cool. Heated rooms in winter are the problem, because warmth and dry air arrive together. The RHS suggests a pebble tray under Christmas houseplants, with the base of the pot kept above the water line, and grouping plants together. Do not mist the crown, which only puts water where it causes rot.

Temperature

Coolness is the single most important factor. Clemson gives ideal days of 60 to 65°F (16 to 18°C) with nights around 50°F (10°C), and says buds fail to develop above 70°F (21°C). The RHS groups indoor cyclamen with plants for bright, cool rooms of 50 to 59°F (10 to 15°C), and NC State recommends about 65°F. In practice that means an unheated bedroom, a cool entry hall or a sill in a room you keep at the low end of comfortable. Keep it away from radiators, fireplaces and heat vents.

Fertilizer

Feed lightly while the plant is in leaf. Clemson, describing the restart after dormancy, fertilizes monthly with a liquid houseplant fertilizer once new leaves grow from mid-September. The RHS continues careful feeding after flowering until the leaves yellow. Stop as the plant enters its summer rest, and do not feed a dormant tuber with no leaves.

Work out the dose for your watering can with the fertilizer dilution calculator →

Repotting

A florist's cyclamen rarely needs a bigger pot in its first year. The time to repot, if ever, is the end of dormancy in late summer, when the tuber starts pushing new leaves; Illinois Extension recommends repotting plants while they are actively growing. Set the tuber at the same level it grew before, with its top at the surface, and use fresh mix. If the pot is still roomy, the RHS approach of only refreshing the top layer is enough.

• The tuber fills the pot and new leaves are smaller than before
• The mix dries out within a day of watering
• Roots grow through the drainage holes

Propagation

Honestly, this is a plant to buy rather than propagate. Clemson discourages growing it from seed even though that is how professional growers do it: germination is slow and erratic, and a flowering plant takes 9 to 15 months even in a greenhouse. NC State notes that fresh seed germinates in roughly three to four weeks, but erratically. Division is no easier, because each tuber has few growing points and cut pieces dry out or rot.

Methods: Fresh seed (slow, 9 to 15 months to a flowering plant), Division of the tuber (risky, prone to rot) · Best season: late summer, at the end of dormancy.

Common problems

Warmth causes most cyclamen trouble: buds that never open, flowers that fade in a week, and spider mites that thrive in warm, dry air. Tuber rot from overwatering, or from watering onto the crown, is the other common killer. Yellowing in late spring is usually dormancy, not a disease. Clemson lists aphids, mealybugs, spider mites and thrips as occasional pests controlled with insecticidal soap, and says a plant with cyclamen mites is best discarded.

Not sure which one it is? Try the plant problem diagnosis tool →

Is the cyclamen toxic to cats and dogs?

The ASPCA lists cyclamen as toxic to cats, dogs and horses. Its toxic principles are terpenoid saponins, causing salivation, vomiting and diarrhea, and the ASPCA warns that large ingestions of tubers can lead to heart rhythm abnormalities, seizures and death. The tuber is the dangerous part, which matters because it sits exposed at the soil surface and dogs sometimes dig up resting tubers. NC State rates it of low severity for people, partly because the taste is unpleasant, and notes that handling can irritate skin. Keep it out of reach of pets and call your veterinarian or the ASPCA Animal Poison Control Center at once if an animal chews the tuber.

Check any other plant against the ASPCA lists →