One of the reasons many of us try to grow cacti is because they are notoriously simple to raise, giving those of us with black thumbs some hope that we can keep something alive. So, when we see our cacti begin to wrinkle we wonder how we were able to kill a cactus!
Many cacti will wrinkle on their own during the winter in order to survive the colder temperatures by using up the water in their stems. They can also wrinkle because of a pest infestation, too much sunlight, being planted during the wrong time of year, and being planted in a pot with a poor soil mixture.
In spite of these numerous causes, there’s hope for us. Once we can pinpoint what the cause behind the wrinkling is, there is usually still time to help the cactus and give it new life.
When a Cactus is being devoured by pests and you don’t notice them in time then the cactus will begin to look shriveled and develop ugly brown scars. What commonly happens is that responsible cactus owners will routinely check their cactus but find no visible pests. Yet, there might have been microscopic creatures that you didn’t see that are eating your little cactus.
One such nuisance is the spider mite which you know you’ll have if you see yellow spots appearing on the leaves, which will eventually die and fall off. They will also leave “spider webs,” hence their name.
If there are no pests visible on the leaves of the cactus, you need to check the roots for root insects such as root mealybugs.
If you haven’t watered your cactus in months, or water it very little, then the cactus will begin to rely on the water it has stored in its stem cells. All cacti have collapsible water storage cells in their stems and in their root systems.
As it consumes the water in these reserves the cactus gets wrinkled because the cells collapse once they’re emptied. You know that the cause of your cactus’s wrinkles is due to it using up the water in its stem cells by the fact that the wrinkles and folds are at the base.
If you’re confident that invisible pests are not the problem, odds are the issue lies within the root system. Cacti are low-maintenance plants but they can easily develop root problems. When you are inspecting the roots of your cacti, the root system should appear white, relatively thick, and should not be too delicate or limp.
There are three kinds of root problems that cause shriveling and wrinkling of the cactus plant: root-eating insects, root rot, and crowded roots. We’ve discussed the insects already.
Root rot happens when a cactus gets too much water, is in soil that doesn’t allow proper drainage, or was planted in soil that contained fungal spores. All of which cause mold or a fungus to grow and rot the roots.
Crowded roots, on the other hand, don’t have soil or watering problems, but are within too small a container, causing the roots to become “root-bound.” They essentially suffocate each other and prevent one another from properly intaking enough nitrogen, causing shriveling.
As we touched on in the last section, Cacti can shrivel or wrinkle if they are in poor soil. It’s possible that when you purchase a bag of soil from a garden center, in spite of all of their precautions, the soil may have diseases, insects, or fungal spores that will hurt the plant. Even peat soil can be infested.
When you purchase potting mix you should sterilize it to kill all of these things. There are a number of ways to sterilize your soil from using the oven, to the microwave, the sun, or chemical sterilizers.
Then there is the mixture itself. The mix should have the right acidity for cacti, which is approximately between 5 and 6 at pH level. Cacti also need a mixture that has essential properties like being nutrient-rich and drains easily.
Like other kinds of plants, Cacti cannot be planted at just any time of year. In temperate climates, they CAN NOT be transplanted between October and February, they should be planted between March and September.
If they are planted between October-February, the cacti will likely die because during this time there is too little sunlight, both in intensity and duration. This prevents the cacti from properly developing their roots and absorbing water and nutrients. This causes root rot that eventually shows itself in the plant with shriveling and wrinkling.
If you notice your cactus or cacti shriveling up in the winter, don’t be alarmed. This is actually normal behavior for cacti. Many types of cacti require a winter dormancy period because they are being cared for in climates that are colder and more humid during the winter than their natural environments.
During this dormant period, the watering of the cactus ceases completely and is kept in a dry, cool place. Meanwhile, the cactus uses up the water in its stem cells and roots (which we said above will cause wrinkles), allowing it to become hardy during the winter months as the less water it has, the lower temperatures it’s able to take. At the end of this dormancy, once you start watering your cacti again like before, they will be encouraged to grow flowers.
It also isn’t unusual for Cacti to begin their dormancy period early, such as in mid or late fall. This isn’t something you should assume, however. Only make this educated guess once you have eliminated the possibility of pests and root issues. One last thing to note is that the epiphytic cacti, or Christmas cacti, still require slight watering about once every 5-6 weeks instead of no watering. Otherwise, they shrivel up completely.
It’s easy for us to think that the best environment for our cacti is somewhere hot and sunny, but this isn’t actually the case. In their natural habitat of the desert, Cacti either grow against huge rock faces that protect them from direct sunlight during the hottest parts of the day or they grow in desserts that have frequent thunderstorms and cloud cover that block the sun.
If you’ve put your cacti in the sunniest places of the yard, they will suffer shock and the pots will heat the cactus roots. While in a state of shock, the cactus will not be able to absorb water or nutrients well, losing its water-retention mechanism, and causing the plant to wrinkle and rot.
Now that you know the most common causes of cactus wrinkling and shriveling, you can work to revive your poor cacti.
You just have to simply move the cactus to a more shaded location, adjust your watering, get or make a better soil mixture, put the cactus in a pot that is either the exact same size or 10% – 15% larger, and/or allow your cactus to go through its winter dormancy.
Now at least, you know that if there’s nothing apparently wrong with your cactus it isn’t your black thumb but a natural behavior of your cactus. When you inspect your prickly friends, be sure to wear thick gardening gloves and use tongs to gently pull up the cactus from the base.