Growli

Plant care

Kalanchoe (flaming Katy) care

Kalanchoe blossfeldiana

Also called flaming Katy, Christmas kalanchoe, Madagascar widow’s thrill.

RHS H1cUSDA 10-12Toxic to petsIndoor 20-40 cm tall

Watering rhythm

10-14days

When the soil is dry, every 10-14 days

Light

Direct sun (at least 4-6 hours)

Soil

Free-draining cactus or succulent mix

Humidity

30-50%

Temp

15-24°C

Pet safety

Toxic to pets

Mature size

20-40 cm tall

Care at a glance

Light

Kalanchoe needs sun on the leaves, not just bright ambient room light. 4-6 hours of bright light, with some direct sun. Insufficient light prevents flowering. A south or west-facing windowsill in the northern hemisphere is the default; anywhere else, expect the plant to stretch and pale out within a season.

Watering

Water kalanchoe when the soil is dry, every 10-14 days. The actual day count varies with pot size, light, and season — the finger test (or lifting the pot to feel its weight) is more reliable than a fixed calendar. Empty any drainage saucer afterwards so the pot isn't sitting in water. Water deeply and let the soil dry between drinks. Cut back further during dormancy.

Soil and pot

Kalanchoe grows best in free-draining cactus or succulent mix. Coarse cactus mix or 1:1 potting compost and perlite. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Kalanchoe sits happiest at around 30-50% humidity and 15-24°C (60-75°F). Dry household air is ideal. If you keep the room above 15 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed kalanchoe sparingly. Half-strength cactus or bloom feed monthly during the growing season; switch to a higher-phosphorus feed when buds form. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on kalanchoe in the Growli community. Each is annotated with the most common cause so you know where to start.

  • No re-bloom after the first floweringKalanchoes need a 6-week period of long nights (14+ hours of darkness) to set new buds.
  • Yellow leavesOverwatering.
  • Drooping leavesUnderwatering after a long dry spell.
  • Leggy growthInsufficient light; move to a sunnier spot.

Companion plants

Kalanchoe pairs well with Jade plant, Aloe vera, and Echeveria. These are species with similar light and water needs, so you can group them in the same room or on the same shelf and water as a batch.

Propagation

Leaf or stem cuttings allowed to callus root readily in dry succulent mix. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Kalanchoe is toxic to pets. ASPCA lists Kalanchoe as toxic to cats, dogs and horses due to cardiac glycosides (bufadienolides). Symptoms include vomiting, diarrhoea, and rarely heart arrhythmia. Veterinary attention if ingested. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Kalanchoe care — frequently asked questions

What is the common name for Kalanchoe blossfeldiana?

Kalanchoe blossfeldiana is most commonly called Kalanchoe, but it is also known as flaming Katy, Christmas kalanchoe, Madagascar widow’s thrill. The names refer to the same species, so care instructions for Kalanchoe apply identically to anything sold as flaming Katy.

How much light does kalanchoe need?

Kalanchoe grows best in direct sun (at least 4-6 hours). 4-6 hours of bright light, with some direct sun. Insufficient light prevents flowering.

How often should I water kalanchoe?

Water kalanchoe when the soil is dry, every 10-14 days. Water deeply and let the soil dry between drinks. Cut back further during dormancy. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is kalanchoe toxic to cats and dogs?

Kalanchoe is toxic to pets. ASPCA lists Kalanchoe as toxic to cats, dogs and horses due to cardiac glycosides (bufadienolides). Symptoms include vomiting, diarrhoea, and rarely heart arrhythmia. Veterinary attention if ingested.

What USDA hardiness zone does kalanchoe grow in?

Kalanchoe is rated for USDA zone 10-12 (indoor-only in most US homes) and RHS hardiness H1c. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Kalanchoe deep-dive guides

Every aspect of kalanchoe care, each with its own calibrated guide:

Featured in these plant shortlists

Kalanchoe qualifies for 6 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Kalanchoe is also known as flaming Katy, Christmas kalanchoe, and Madagascar widow’s thrill.