Bell kalanchoe is the drooping, lantern-flowered member of the family, and it is a succulent wearing a florist’s label. Everything about its care follows from water storage in the leaf, which makes the gardener’s instinct to help with a watering can the main threat to the plant.
Soil and water
Soil is not a difficulty, except that heavy sticky mixes rot it quickly. The working potting mix is humus and garden soil with about 5 per cent coarse sand through it, and a base of bone meal or a few nitrogen-phosphorus-potassium pellets at the bottom of the pot.
Watering is the discipline. This plant handles drought far better than wet, and a dry flat does it no harm at all. Do not water on a two or three day habit; keep the pot on the dry side and follow the rule of letting it dry and then watering through, thoroughly, to the drainage hole. In spring and autumn that means a drink whenever the pot has dried, and five to seven days is a good interval for a plant standing outside. When summer heat is high, water in the cool of the evening rather than midday, because warm wet soil is what cooks the roots. A balcony plant must be tipped out of any saucer after rain.
Light, and the turned pot
Full sun, half sun or bright scattered light will all produce a plant, but this one prefers sun: apart from high summer, a balcony position with at least four hours is what keeps it flowered. Half a month, turn the pot, so the crown fills evenly instead of leaning into the window and losing its shape.
Too little light is not a slow plant, it is a specific failure: leaves drop, the colour pales, flowering is late or absent altogether. When that shows up, more light is the correction, not more food.
Temperature, the flowering switch
Fifteen to twenty-five degrees is comfortable. Above 30 °C growth effectively stops and the plant sits half-asleep through the hot weeks. Below 10 °C it stagnates; at 8 °C the leaves redden and flowering is pushed back; near 0 °C it takes frost damage. The practical sequence runs from September, when light should be increasing rather than less, and from the first time the pot goes below 10 °C it comes inside to the brightest position, holding about 10 °C at night and 15 to 18 °C by day. That combination is what brings bells in December.
Feeding, and one caution
Summer means no fertilizer at all. Through the rest of the growth period a balanced, weak feed is right, and during flowering a thin monthly application of a complete fertilizer keeps the display going. The caution is application: fertilizer landing on the leaf will rot that leaf, so water it off immediately if any splashes the foliage.
As the stems lengthen and the bloom clusters get heavier, put a support in. An unstaking plant falls east and west, and a bell kalanchoe that has collapsed to one side of the pot cannot be corrected without cutting it back. Propagation timing for this kind of plant is covered at the best season to propagate succulents, feeding strength at nitrogen, phosphorus and potassium, and the cool-dry finish that produces the flowers is the same argument as clivia in winter.
