TROUBLESHOOTING COMMON CHRISTMAS CACTUS CONCERNS
While they are technically a cactus, Christmas cacti don't naturally live in the desert like other cacti. They originate from coastal tropical rainforests in Brazil. If you're struggling to keep your Christmas cactus happy, here are some of the most common problems that Christmas cactuses have and what to do about them.
FUNGAL OR DISEASE PROBLEMS
Generally, holiday cactuses are quite resilient and don't have too many problems with diseases. Here are the few fungal or disease issues they can be affected by:
HOLIDAY CACTUS STEM ROT
Looks like: soft brown watery spots on the stem of the plant, usually near the base.
Caused by: It is usually caused by cool, damp soil from overwatering.
Solution: Stem rot is very difficult to treat, and usually, your best bet is to start a new plant from healthy leaf cuttings. If you want to try to save the mother plant, take some cuttings first and start them in a new pot, just in case. Then, try to cut out the rotted piece of stem. Make sure you get all the rotted squishy brown bits out. If you don't, it will only spread and kill the plant. There's a good chance it will die anyway, even if you manage to cut out the rot.
HOLIDAY CACTUS ROOT ROT
Looks like: wilting leaves, soggy soil, black or reddish spots, or brown leaves.
Caused by: overwatering
Solution: if you suspect root rot, the best bet is to immediately remove the cactus from its pot, rinse the soil off the roots, and cut off any chunks of roots that are squishy and rotten. Then, repot in barely moist soil in a clean pot with drainage holes. Make sure to use cactus soil and reduce watering frequency. Don't water until the soil is dry, and remove any excess water from the drip tray half an hour after watering.
Both stem rot and root rot are fungal problems, but fungicides aren't usually effective. You'd need to be able to identify the exact pathogen causing the fungal problem to choose the right fungicide, and it's easier and faster to repot or start new plants in clean soil and pots.
BOTRYTIS BLIGHT, OR GRAY MOLD
Looks like: a silvery gray fungus or spots of mold all over the leaves
Caused by: Botrytis blight is a fungal infection. It thrives on decaying foliage and spreads as spores. Very high humidity and getting the leaves wet makes a plant more susceptible.
Solution: plants with Botrytis blight should be discarded and destroyed immediately. Make sure to sanitize the pot with bleach if you intend to reuse it. You can help prevent Botrytis blight by improving ventilation and air circulation.
NECROTIC SPOT VIRUS
Looks like: yellow spots on wilted leaves and stems.
Caused by: infected thrips.
Solution: isolate your plant and use an appropriate insecticide to deal with thrips. Purchase new soil, and repot your plant in a clean pot. Discard the soil in your garbage bin, tied shut in a black bag. If you want to use the pot again, make sure you sanitize it with bleach.
NON-DISEASE PROBLEMS
Here are some of the other non-disease related problems that holiday cactuses may have. These problems are usually easily solved by some adjustments to the environment or care for your Christmas cactuses.
LIMP OR WILTING CHRISTMAS CACTUS
If your Christmas cactus is wilting or seems very limp, it could be one of three issues. You'll want to identify and address the problem quickly, as it could potentially turn into root or stem rot if left alone.
The soil could be too wet, or too dry, or it may be too rootbound. Feel the soil with your finger, to about an inch deep, and use the process of elimination to determine the problem.
Solution: If the soil is just damp, let it dry before watering again. If the soil is saturated, it's best to immediately remove it from the saturated soil and repot it into dryer soil to prevent root or stem rot.
If the soil is dry, water it and watch it for a few days.
If there is no improvement after watering, the cactus may be very root-bound. Holiday cacti do like to be root bound, but eventually, they get too constricted to stay healthy. If your plant perks up and then wilts again within a few days, or if it doesn't perk up from watering, try repotting it into a new pot with a drainage hole one size bigger with cactus soil.
CHRISTMAS CACTUS LEAVES TURNING RED OR PINK
If the leaves of your Christmas cactus are turning red or pink, it may be getting too much sun, or it may not be getting watered enough.
Solution: If your Christmas cactus is right next to a window that gets direct sun during the day, move it back. They can take a bit of sun, but they prefer indirect light. Check the soil as well, and if it's dry to one inch deep, water it more frequently. When the soil feels dry to the touch, water your Christmas cactus.
CHRISTMAS CACTUS WON'T BLOOM
If your Christmas cactus won't bloom, there could be a few different factors affecting it. Christmas cactus like to be a little bit rootbound, they like consistent temperatures, they want to be left alone, and they need long periods of darkness in the fall to initiate their blooming sequence. The older a Christmas cactus is, the more likely and profusely it is to bloom, so if you've just brought a small plant home, be patient!
Here are a few steps you can take to encourage your Christmas cactus to bloom in time for Christmas.
Cut back on watering in mid-October; only water when the soil is dry to about 1 inch deep.
Keep the temperature reasonably cool, between 50-60ºF.
Keep it in indirect light during the day, and give it 12-14 hours of darkness at night for 6-8 weeks.
If you have windows in the room, close the blinds at night. If there is still lots of ambient light, even with blinds/curtains closed, you can gently cover the plant itself with dark cloth or bag. If you're going to use a blanket or sheet, place some sort of a frame around the plant, even putting it between two kitchen chairs so the cover doesn't cause any breakage.
Once you start to see flower buds forming, you can stop covering it at night.
When the buds start to open, return to watering when the surface of the soil feels dry
CHRISTMAS CACTUS DROPPING FLOWER BUDS
Suppose your Christmas cactus creates flower buds, but they all fall off before it blooms. In that case, it could be caused by sudden changes in light, humidity, temperature, overwatering, or being relocated.
If you recently brought your Christmas cactus home, moved to a new home, or moved it to a new room, you'll just have to be patient. They don't like sudden changes in environment and prefer to be left alone, so eventually, it will create new buds and flowers again.
If your cactus has been overwatered, it may drop its buds. If the soil is damp, leave it to dry before watering. If the soil is saturated, immediately repot it into barely moist cactus soil, so it doesn't get root rot. It may still drop its buds, but it should get new buds again eventually.
If the humidity has suddenly changed in your home (like if you just turned the furnace on recently), your Christmas cactus may have dropped its buds because it needs more humidity. Run a humidifier in the room, or place your Christmas cactus on a pebble tray.
CHRISTMAS CACTUS PESTS
Christmas cactuses may get infestations of common houseplant pests just like any other houseplant. If you see signs of an infestation, isolate your plant and treat the infestation with your preferred product.