The Christmas cactus (Schlumbergera x buckleyi) and its relative, the Thanksgiving cactus (Schlumbergera truncata), have the reputation of being easy-to-care for, low-maintenance houseplants whose vibrant flowers brighten up the long, dark winter days. But sometimes the leaves, instead of looking plump and succulent, are limp and wilted. It is always a warning sign that something in the growing conditions is off kilter. The earlier you identify the underlying problem and take corrective action, the better.
Here are the five most common reasons for why a Christmas cactus has limp leaves.
The Christmas cactus is an epiphyte—a plant whose shallow, delicate root system sits above the ground, supported by another plant or object. The substrate in which the Christmas cactus is growing in its natural habitat provides excellent drainage. However, when you grow it as a houseplant, in the confined space of a pot, the soil can get waterlogged and soggy. If the plant is given more water than the leaves can absorb, they turn limp as a result.
Because limp leaves can also be a sign of the exact opposite—underwatering—you cannot tell from looking the leaves alone that the plant has been overwatered. You need to inspect the soil instead. If it feels and looks wet, you have watered the plant too much.
What you should do next to remedy it depends on how long you’ve overwatered the plant and how well the soil drains. No matter how good the drainage, repeated excessive watering over a long time can lead to root rot and stem rot.
Carefully lift the cactus with its entire root ball out of the pot and shake off the soil to check the roots for signs of softness and rotting. If the overwatering was merely temporary, you can return the plant to the pot. Make sure the pot has large drainage holes; if it doesn’t, switch to another pot. Wait for a couple of days before resuming the watering routine and adjust it so you don’t overwater the plant again.
If the potting mix is too dense and compacted around the roots, which can happen to older plants over time, repot the Christmas cactus with fresh cactus soil, which is airy and fast-draining. You can also mix 60 to 80% regular potting mix with 40 to 20% perlite.
Limp leaves can also be caused when you have not watered the plant enough. The rule of thumb is that the top 2 inches of soil should dry out between waterings but if the soil is bone dry all the way to the bottom of the pot, the leaves become limp, indicating a severe lack of water.
The Christmas cactus being a tropical plant, it needs more water than other cacti. The watering frequency depends on the temperature as well as the stage where the plant is in its growing season. During the active growing period and the flowering time, the Christmas cactus needs more water than in the post-flowering period. In a cool room during the winter, weekly watering might be sufficient whereas during the hot summer months, watering it two to three times per week will be needed. Always check the soil moisture to decide, and water slowly and thoroughly until the water drips out of the drainage holes.
Too Much Sunlight
Exposure to full sunlight during the summer months causes the leaves to become limp. Move the plant to a location with partial shade or bright, indirect light where it is able to recover. In the fall and winter, holiday cacti can tolerate full sunlight better.
Lack of Humidity
Dry air, especially in a heated home or office during the fall and winter can be another cause for limp foliage. The native habitat of the Christmas cactus in Brazil has high humidity; its foliage draws moisture from the air. In a room with low humidity, the leaves shrivel and drop, and the plant also fails to set flowers.
If you don’t have a humidifier running in your home during the heating season, mist the plant at least twice daily, or place the pot on a tray of damp aquarium gravel.
If you can rule out overwatering, underwatering, too much sunlight, and low indoor humidity, your Christmas cactus might simply be rootbound. The Christmas cactus is a long-lived plant and if you do not repot it about once every three years, it is likely to become rootbound. Crowded, girdling, crisscrossing roots struggle to take up water and nutrients, and as a result, the leaves become limp.
After repotting your holiday cactus in a larger pot with fresh cactus soil, the foliage should recover soon.
Thanksgiving Christmas Cacti. Clemson University Cooperative Extension