Kalanchoe care: light, water and reblooming

Light

Give it as much light as you can indoors. Clemson says kalanchoe grows best in full sun and tolerates bright indoor light, but gets spindly in low light. On the University of Illinois Extension scale, aim for at least high light, about 300 foot-candles, directly in front of an east or west window, or better, direct light in a south window. NC State says that to keep it blooming it should receive 6 to 8 hours of bright light every day.

Sources differ on hot sun. NC State prefers bright indirect light or partial shade and warns that prolonged direct sun can scorch the leaves, recommending afternoon shade outdoors, while Missouri Botanical Garden lists full sun or bright indirect light for indoor plants. A sunny windowsill is usually fine in winter; in summer, or outside on a patio, shade it from the hottest afternoon hours and introduce it gradually, as Clemson advises, so tender leaves do not burn.

Water

Water deeply, then let the mix dry before the next watering. NC State says to let the soil dry out between waterings and then water deeply, and Missouri Botanical Garden gives the same advice. Clemson is slightly more generous, saying to allow the soil to dry slightly, but all three agree that overwatering is the danger: it leads to root rot and stem rot, the most common way kalanchoes die.

Empty the saucer every time. Clemson notes that root rot usually comes from a mix that does not drain quickly or from watering too often, and that plants should never sit in water. Foil-wrapped florist pots are a trap here, because they hold drained water around the roots; remove the foil or punch a hole in it.

Cut back in winter and while the plant is setting buds. Missouri Botanical Garden recommends less water and less fertilizer during periods of slow winter growth and while flowering is being triggered. The thick leaves carry the plant through dry spells, so err on the dry side when in doubt.

Soil and pH

Use a mix that drains fast and holds plenty of air. NC State recommends a well-drained potting mix suited to cactus and succulents, and Clemson suggests a well-aerated blend such as 60% peat moss and 40% perlite. Missouri Botanical Garden stresses very well-drained soil. Avoid heavy, moisture-retentive bagged mixes, and always use a pot with a drainage hole.

Humidity

Humidity does not matter much for this succulent. NC State describes the genus as preferring indoor sites with dry soil and low relative humidity, so the dry air of a heated home in winter is fine. Do not mist; damp leaves and still air encourage the powdery mildew that Clemson and NC State both mention. Good air movement around the plant is more useful than added moisture.

Temperature

NC State and Missouri Botanical Garden both give 60°F at night and 70°F during the day as the ideal, and Missouri Botanical Garden notes that temperatures too low or too high can inhibit flowering. Clemson gives a cooler range, 45 to 65°F at night and 50 to 70°F by day, and adds that cool nights prolong the life of the flowers. NC State says to bring plants indoors before temperatures drop to 45°F. During the long-night period, Clemson warns that nights above 80°F cause a heat delay that holds back flower buds.

Fertilizer

Clemson recommends feeding actively growing plants with any houseplant fertilizer once a month. Missouri Botanical Garden suggests a well-balanced fertilizer or one higher in phosphorus to promote flowering, and less fertilizer during winter and while flowering is being triggered. A plant in full bloom from the florist needs no feeding at all until the flowers finish and new growth starts.

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

Repotting

Repot after flowering rather than during it. Clemson's advice is to shift the plant to a slightly larger pot once the blooms are done, cut back tall growth and old flower stems, and keep it watered in a sunny, warm window. Use fresh, well-aerated mix. A pot only slightly larger keeps the volume of wet mix around the roots small, which matters for a plant so prone to rot.

• Flowering has finished and the plant is top-heavy for its pot
• Roots circle the bottom or grow out of the drainage hole
• The mix stays wet for days after watering

Propagation

Stem cuttings are reliable. Clemson recommends taking terminal cuttings two to three inches long with two pairs of leaves, from vegetative rather than flowering shoots, in spring or early summer. Strip the bottom leaves, let the cut end callus for several days, and insert the cuttings in a mix of half peat moss and half perlite; no rooting hormone is needed. Kept in bright, indirect light inside a closed plastic bag, they are ready to transplant in 14 to 21 days.

NC State adds that leaf cuttings also work, and Missouri Botanical Garden notes that small plantlets sometimes appear at the leaf margins and can be potted up on their own.

Methods: Stem tip cuttings, Leaf cuttings, Plantlets from leaf margins · Best season: spring or early summer.

Common problems

Most trouble comes from water, light or the calendar. Rot follows overwatering, spindly stems follow low light, and a plant that never reblooms usually has not had long enough dark nights. Clemson names mealybugs, aphids and brown scale as the most common pests; brown scale can be scraped off and aphids removed by hand. Powdery mildew is easy to miss on kalanchoe because it shows only as fine webbing with mottled, spotted leaves, and the plant may be stunted and fail to flower.

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

Is the kalanchoe toxic to cats and dogs?

Kalanchoe is toxic to pets. The ASPCA lists the genus as toxic to cats and dogs, with bufodienolides as the toxic principle and vomiting, diarrhea and, rarely, abnormal heart rhythm as clinical signs. NC State goes further, warning that ingestion by pets can be fatal, with abnormal heart rate and seizures, and rates the plant of medium severity for people, with every part poisonous. Keep it out of reach of cats, dogs and children, wear gloves when handling it, and call your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 right away if a pet eats any.

Check any other plant against the ASPCA lists →