Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
Does your house look empty and dull after you clear away the holiday decorations? Then you need at least one kalanchoe plant! Like poinsettias, they are light sensitive, needing 16 to 18 hours of continuous darkness before they bloom. Long winter nights are perfect for coaxing them to bud and then burst into colorful bloom in January as the days start to get longer.
What is Kalanchoe?
Kalanchoes are succulents that are native to the island of Madagascar. Their leaves are slightly thickened and waxy to conserve moisture in an arid environment. The plants can be grown outdoors in growing zones 7 through 11. They are very sensitive to the cold, preferring temperatures ranging from 60 to 85 degrees Farenheit. Grow them in partial shade. Full sunlight will burn their leaves.
In colder climates, kalanchoes can be grown as houseplants, either indoors entirely, or brought outdoors during the summers only. Indoors, grow them on a sunny windowsill.
With just a little care, you will be rewarded with years of vibrant four petal flowers in red, pink, white, yellow or orange. There are even double varieties available. My kalanchoe is nearly ten years old. It delights me every year with bright pink flowers.
How to Grow Kalanchoe
Outdoors, grow kalanchoe in partial shade. Indoors, grow them in indirect light, similar to African violets. If your plant gets long and spindly, it’s not getting enough light. Move it to a sunnier spot or provide artificial light. I grow my kalanchoe in a north facing window with my African violets.
Kalanchoe need well-drained soil. Soil that is too wet will cause the roots to rot. Only water when the top of the soil dries out. Fertilize monthly with any houseplant fertilizer.
After your plant finishes blooming, clip off the dead flower stalks and any other dead foliage. Allow it to rest, with no fertilizer, for a few months until it starts growing again. When you see new growth, you can resume fertilizing.
How to Make Kalanchoe Bloom
Kalanchoes are light sensitive. They need 16 to 18 hours of complete darkness to set their buds and then begin blooming. Grow them in a room that is dark at night, with no artificial light. A family room where you watch TV in the evenings is not suitable. A rarely used guest room would be a good spot.
I grow mine in my home office. Since I work from home, I leave my office between 5 pm and 6 pm each day. No lights are turned on in the room after I leave. The long hours of winter darkness are just what my plant needs. Each January, it bursts into bloom.
If you don’t have a room that is completely dark at night, you can put your plant in a windowless closet at night to provide the complete darkness that it needs. Just remember to take it out of the closet in the morning!
How to Grow Kalanchoe From Cuttings
It’s easy to root cuttings from your kalanchoe. Snip off a branch that is not flowering. Remove any leaves on the lower 2 inches. Make sure that there are at least 2 pairs of leaves left. Leave the cutting out for a few days to allow it to “callous” which means that the cut end will dry out. The allous protects the cutting by blocking disease from entering the plant. Once it has dried, you can dip it in rooting hormone if you have it and then gently push it into the soil of a pot. Moisten the soil and then cover the pot with a plastic bag that has some slits cut into it. The plastic bag will provide a humid environment for your cutting, kind of like a mini greenhouse. Place the plastic covered pot on a sunny windowsill, checking the soil periodically to make sure that it remains moist. Roots should start growing in 2 to 3 weeks. You will know that new roots are growing by the new leaves that are growing. Plants only produce new growth when they have roots. If they have no roots like a cutting, they will put their energy into making roots rather than make new leaves.
How to Grow Kalanchoe From Seed
Kalanchoe can be grown from seed with a little care. In early spring, as the number of daylight hours are lengthening, start your seeds indoors. Moisten soil in a container and surface sow the seeds. Do not cover the seeds. They need sunlight to germinate. Put the container in a plastic bag to create a humid environment for the seeds. Germination should occur within 10 days. Within two months, the seedlings will be large enough to transplant either into a container or outdoors if you live in a warm climate.
It is important to keep in mind that the seeds should be sown when there is adequate sunlight. If you sow your seeds during the dark winter months, it will confuse the seedlings and they will not grow properly, if at all.
Questions & Answers
Question: I am staying in south India. Which months I should keep the kalanchoe plant in the dark & how many days in that particular month?
Answer: Lucky for gardeners, plants don't have calendars. You can fool plants into thinking it's a completely different season. So you may choose when you want your plant to bloom. Keep it in the dark for 16 to 18 hours per day for about a month and it should start to bud and then bloom for you.
Question: Should I water the plants during the resting period?
Answer: Yes, you should continue to water your plant while it is resting. If you do not water it, it will die.
© 2017 Caren White
Caren White (author) on March 04, 2020:
My philosophy has always been "if it ain't broke, don't fix it". The fact that your plants bloom every year means that you are doing everything right. I don't know what the climate is like in Spain, but I'm going to assume that you get more hours of daylight during the summer and fewer hours of daylight in the winter. It could be that your plants are getting just enough hours of darkness during the winter even though they are outside that is sufficient for them to bloom. So don't change anything and just continue to enjoy your plants.
Cheryl on March 03, 2020:
I have the red double petal kalanchoe that looks like little roses. I have always kept my two plants outside in full sun in Spain, in containers. They flower every year. I have just read here that they require 16-18 hrs of darkness to start flowering. Does this mean that I would probably have more blooms if I did this?
Caren White (author) on June 09, 2018:
No it doesn't make it less healthy but it does make it non-organic. If you wish to maintain organic standards, you need to use a natural rooting hormone such as willow bark extract.
Abril on June 08, 2018:
Hi, I would like to know if adding rooting hormones does it make it less healthy to eat these leaves later??
angela pecchia on February 09, 2017:
thanks for the help :)
Caren White (author) on February 07, 2017:
It's a question of hours of darkness rather than age that determines when your kalanchoe will bloom. Make sure that it is in complete darkness for at least 16 hours each night. Mine is in a room that I only use during the day. There are no lights on at night.
angela on February 06, 2017:
hi! I started kalanchoe plants from cuttings and they are about 10" tall but haven't flowered yet. they are about 5 months old. i was just wondering if you knew how old they are when they start flowering?
Caren White (author) on January 12, 2017:
Hope this helps! Thanks for reading and commenting.
Jill Spencer from United States on January 12, 2017:
Thanks for these tips, Old Roses. I have several kalanchoe-- they are hard to resist at the grocery store!-- and have been wondering how to make them bloom more. Best, Jill