Kalanchoe Care: Make Flaming Katy Rebloom

Kalanchoe is easy to keep going and can flower year after year. The Flaming Katy (Kalanchoe blossfeldiana) usually arrives from the supermarket covered in flowers, fades after a few weeks and never blooms again. That’s not your fault. It just needs long, dark nights to set new buds.

Get the light, water and darkness right and one cheap plant gives you colour every winter. This guide covers watering, light, compost, making it rebloom and taking free plants from cuttings. If you grow other short-day plants, the Christmas cactus care guide works on the same idea.

Why your Flaming Katy stopped flowering

Kalanchoe stops flowering because your home has too much light in the evening. It is a short-day plant, which means it only forms buds after several weeks of long, unbroken nights. Nurseries trigger flowering with blackout screens, then send it to the shops in full bloom.

On your windowsill, the lamps, hall lights and even street light through thin curtains keep its nights short. It grows happily but sets no buds. Feeding and watering harder only gives leggy green growth. Give it about 14 hours of total darkness each night for six weeks and it flowers again. The method is below.

What is a Flaming Katy?

Flaming Katy is a succulent from Madagascar. It grows about 30cm tall as a houseplant, with thick, glossy, scallop-edged leaves that store water. Those fleshy leaves are why it copes with dry spells far better than with soggy compost.

The flowers sit in dense clusters above the leaves, in red, orange, pink, yellow, salmon or white. Double-flowered types are sold as Calandiva. Two relatives also turn up as houseplants: the felty grey panda plant (K. tomentosa), grown for its leaves, and mother of thousands (K. daigremontiana), which sprouts tiny plantlets along its leaf edges.

Each tight cluster is made of dozens of small four-petalled flowers. A bright windowsill keeps the colour going for weeks.

How to water kalanchoe

Water kalanchoe only when the compost has dried out, then soak it. This soak and dry method suits all succulents. Overwatering kills far more kalanchoe than forgetting.

Push a finger into the compost. When the top 3cm feels dry, water at the sink until it runs out of the drainage holes, then let it drain. Tip away anything left in the saucer. In a warm room in summer that might be every week or so. In a cool room in winter it can be every few weeks.

The leaves tell you how you are doing. Firm, plump leaves mean all is well. Soft, wrinkled leaves mean it is thirsty, and they perk up within a day of a drink. Yellow, mushy lower leaves mean too much water. When in doubt, wait. The jade plant care guide shows the same signs on another popular succulent.

Water at the sink and let it drain right through. Then leave it alone until the top of the compost is dry again.

Light, warmth and compost

Give kalanchoe the brightest windowsill you have. A south, east or west-facing window keeps it compact and flowering well. In poor light the stems stretch, the leaves spread out and flowers don’t form.

Keep it between about 15°C and 24°C most of the year, and never below 10°C for long. Cold, wet compost leads to rot, so an unheated porch or conservatory is risky in winter. Move it off cold glass on frosty nights, and away from hot radiators.

Use gritty, free-draining compost, such as two parts peat-free houseplant compost to one part grit or perlite. Pick a pot only slightly bigger than the roots. Terracotta dries out faster than plastic, which helps. Feed monthly from May to September with a high-potash feed such as tomato feed at half strength. The houseplant feeding guide explains when to feed and when to stop.

Repot in spring into a gritty mix. Firm it gently round the roots and keep the stem base clear of wet compost.

How to make kalanchoe rebloom

To make a kalanchoe flower again, give it 14 hours of total darkness every night for about six weeks. It won’t rebloom on its own in a lit home, but this costs nothing and works well.

1. Start in late September or October. Each evening, put the plant in a cupboard or under an upturned cardboard box, from about 5pm to 7am. No light at all.
2. Give it bright light by day. Bring it back to a sunny windowsill each morning. It needs daytime light to fuel the flowers.
3. Keep it warm and fairly dry. Keep the room at about 15-20°C and water sparingly.
4. Watch for buds after about five weeks. Tiny buds appear at the stem tips. Once you can see them clearly, stop the dark treatment.
5. Enjoy the flowers. Grow it on a bright windowsill and the buds open over the following weeks.

The big mistake is giving up too soon or letting light leak in. One evening under a lamp can set the count back. Stick with it for the full six weeks.

Into a dark cupboard each evening and back to the window each morning. After about six weeks, tiny buds start to show.

Kalanchoe types for your windowsill

Flaming Katy (K. blossfeldiana) is the one to grow for winter flowers. Calandiva types have double, rose-like flowers and are cared for the same way. The panda plant (K. tomentosa) is grown for its soft grey leaves and rarely flowers indoors, but it shrugs off neglect. Mother of thousands (K. daigremontiana) drops so many plantlets that it soon pops up in nearby pots, so keep it on its own.

The panda plant is grown for its fuzzy grey leaves rather than flowers. It’s one of the toughest kalanchoes you can buy.

Month-by-month kalanchoe care calendar

How to take kalanchoe cuttings

Kalanchoe is one of the easiest houseplants to propagate. Both stem cuttings and leaf cuttings root within a few weeks. The best time is May to August, when the plant is growing strongly.

For a stem cutting, snip a healthy shoot tip about 5-8cm long without flowers. Remove the lowest leaves and leave it on a windowsill for a day so the cut end dries and seals. This stops it rotting. Push it into gritty compost and keep it warm and barely moist.

For a leaf cutting, pull off a whole, firm leaf, let it dry for a day, then lay it on gritty compost with the base touching the surface. Tiny roots and plantlets grow from the base. Pot them up once they have roots of their own. The guide to propagating houseplants covers more methods.

Stem cuttings go upright into the grit and whole leaves lie flat on top. The same method works for every kalanchoe, including the panda plant shown here.

Mealybug and other kalanchoe problems

Kalanchoe stays healthy in the right spot, but a few problems turn up. The most common pest indoors is mealybug: small insects that look like blobs of white cotton wool in the leaf joints. They suck sap, leave sticky honeydew and spread to nearby succulents.

Catch it early. Wipe the insects off with a cotton bud and check every joint, as the eggs hide deep in the crevices. Keep an affected plant away from others until it’s clear. If they keep coming back, use an approved product for mealybug and follow the label. The mealybug guide covers the full plan.

Other problems come down to water and light:

• Soft brown rot at the stem base: wet compost in a cold room.
• Pale, stretched growth: not enough light.
• Dropped buds: a move, a cold draught or hot, dry air by a radiator while in bud.

Mealybug looks like tufts of cotton wool tucked into the leaf joints. Wipe it off as soon as you spot it.

Warning: Kalanchoe is toxic to cats and dogs. Keep it on a high shelf out of reach and call your vet straight away if a pet chews it.

Common kalanchoe mistakes

1. Overwatering. Treating it like a leafy houseplant rots the roots. Water only when the top 3cm is dry.
2. Expecting it to rebloom on its own. In a lit home it won’t. Give it 14-hour nights from October.
3. Too little light. On a dim shelf it grows pale and leggy and won’t flower.
4. Light leaking into the dark nights. A hall light or lamp breaks the count. The darkness must be total.
5. Cold and wet together. Below 10°C with wet compost, the plant collapses. Keep it warm and on the dry side in winter.

Now your Flaming Katy is set to flower again, read the guide to caring for succulents indoors for more easy plants that like the same bright light and light touch with the watering can. There are more ideas in the houseplants section.

Frequently asked questions

How do you care for a kalanchoe (Flaming Katy)?

Give it bright light, water only when dry, and keep it above 10°C. Stand it on a sunny windowsill and let the compost dry between waterings. Feed monthly in summer. It stores water in its leaves, so it hates sitting wet.

Why has my kalanchoe stopped flowering?

It needs long nights to set flower buds again. Kalanchoe only flowers after several weeks of long, unbroken darkness. In a lit home it stays in leafy mode. You have to give it short days by hand to make it bloom again.

How do you make a kalanchoe flower again?

Give it 14 hours of total darkness each night for about six weeks. From October, put it in a dark cupboard or under a box each evening. Bring it back to bright light by day. Once buds show, grow it normally and they open over the following weeks.

How often should you water a kalanchoe?

Water only when the top 3cm of compost is dry. In summer that may be every week or so, and in winter every few weeks. Soak the compost, let it drain fully and never leave the pot in water.

Is kalanchoe poisonous to cats and dogs?

Yes, kalanchoe is toxic to cats and dogs if eaten. It can cause drooling, vomiting and lethargy, and large amounts can affect the heart. Keep it out of reach, and ring your vet straight away if a pet chews it.

Can you grow kalanchoe from cuttings?

Yes, stem and leaf cuttings root easily in a few weeks. Let the cut end dry for a day, then push it into gritty compost. Keep it warm and barely moist. Late spring and summer are the best times.

Can kalanchoe live outside in the UK?

Only in summer, as it is tender and can’t take cold. Stand it outside in a sheltered, sunny spot from June to September once nights stay above 10°C. Bring it back in before nights turn chilly.