Tips to keep a kalanchoe plant blooming
Question: My 8-year-old neighbor gave me a flowering kalanchoe plant for my 90th birthday last September. It's in a 3 1/2-inch plastic pot with cactus soil that's hard as a rock. I water it when it's completely dry by soaking it until the water drains out the bottom. It's growing, but it doesn't look too well and has long since stopped flowering. I have a bag of regular cactus potting soil I can transplant it with. What size pot do I need? Is a clay pot better than plastic?
Answer: Kalanchoe are wonderful flowering plants that are often found at florist shops year-round. Caring for these tough plants isn't difficult, but it does require a bit of finesse, especially if you want the plant to bloom again.
Though kalanchoes have thick, succulent leaves, they are not cacti, and actually tend to do better in standard potting mix, rather than a cactus-specific potting soil. I suggest repotting your kalanchoe into a 6-inch pot using regular, high-quality potting soil, not the cactus mix you have on-hand. A clay pot would be fine, but it isn't necessary. Standard plastic or even a decorative glazed ceramic pot would work, though no matter what type of container you choose, make sure there's a drainage hole in the bottom.
If you plan to put your potted kalanchoe outdoors for the summer, however, I would not recommend using a clay pot as they dry out far too quickly.
Kalanchoe plants should be watered every 10-14 days. Don't let it become dry to the point of wilting as that can cause major stress to the plant and affect future flower production.
Fertilize your plant using a liquid organic houseplant fertilizer once per month from March through August. Never fertilize houseplants during the winter months when they aren't actively growing.
The trickiest part about growing kalanchoes is encouraging them to bloom again. Like poinsettias, kalanchoes are photoperiodic, meaning their flower production is dependant on the day length. Kalanchoe are short-day plants that produce flower buds when the day length shortens in the autumn and winter. The kalanchoes you see in bloom at the flower shop at other times of the year are forced to bloom at a particular time by artificially subjecting the plants to shorter “day lengths” via a precisely controlled lighting system.
In order to ensure your kalanchoe blooms again this coming winter, as soon as August arrives, keep the plant in a room that only receives natural light. This means, you can't even turn a lamp on in the room or have a porch light on outside the window at night. Many varieties of kalanchoe will come into flower naturally as the day lengths shorten in the autumn, as long as they don't receive any light at all after the sun goes down.
If this isn't possible, you can put the plant in a dark closet for 12-14 hours per day for two to three weeks. You'll know the treatment was successful if flower buds appear about 6-8 weeks later.
Though kalanchoes aren't quite as sensitive as poinsettias when it comes to day length and flower production, ensuring more blooms is definitely an art of perseverance and consistently. Missing even a single day of darkness is often enough to keep the plant from producing blooms.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio with Doug Oster. She is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden,” “Good Bug, Bad Bug,” and her newest title, “Container Gardening Complete.” Her website is jessicawalliser.com. Send your gardening or landscaping questions to firstname.lastname@example.org or The Good Earth, 622 Cabin Hill Drive, Greensburg, PA 15601.