Who doesn’t love growing things? Unfortunately, for many of us who don’t have a green thumb, it may be challenging to keep plants alive. However, a cactus is an example of one plant that is low-maintenance and is often recommended for new plant growers. But, even though cacti are easy to care for, you still need to remain mindful of how much water you give them, just like any other plant.
What are the signs that a cactus is overwatered? Five signs will let you know a cactus is receiving too much water:
- The skin of the cactus is mushy and puckered
- Soil stays moist for too long
- Cactus is starting to die in winter
- Black/brown discoloration, especially at the base
Because cacti are very drought-tolerant, they need far less water than you think. The remainder of this article will discuss the reasons why these succulents do not need a lot of water, and signs that your plant may be getting too much water. With a few simple steps, you can still save your plant and get it to perk back up!
Why does a cactus need limited water?
A cactus is part of the succulent plant family, which thrives on very little water by storing most of what they absorb beneath their skin. This is an adaptation for plants that evolved in low-water areas such as desserts or steppes. When they cannot rely on much water from the sky or the ground, they need to keep as much as possible to last them through the months-long dry seasons.
Cacti, specifically, are succulents that are covered in spines. These spines can be thick and large, small, and soft, and everywhere in between. They grow from areoles spaced out along the skin and serve several purposes, including helping cacti absorb every water droplet in receives.
Since the spines have 360 degrees of surface area, they can prevent water from running down off the plant and into the ground. Instead, they can direct the water to where it can be more easily absorbed by the cactus.
Another feature that helps keep the cactus hydrated is its waxy skin. This coating prevents moisture from leaving once it has been absorbed.
The cactus has a root system that is also specially designed for absorbing water. With a shallow and extensive root system, the plant doesn’t have to wait for the water to sink in too far before they get to it. This is especially important for desert-dwelling plants because rainfall is less likely to soak into the lower layers of dirt than it is to be evaporated by the hot sun and dry air.
Taproots aid in stabilizing larger columnar cacti. These also help the large cactus store even more water to support its massive size.
Another feature of cacti’s skin allows them to employ a unique breathing process. As we know, all plants intake carbon dioxide (CO2) and expel oxygen (O2). Typical plants do this during the daytime as part of photosynthesis, or the chemical process by which plants use light from the sun to synthesize foods from carbon dioxide and water.
Cacti do not breathe during the day because while this would allow CO2 to enter the plant, and would allow precious water to escape via transpiration. Instead, they use crassulacean acid metabolism(CAM), which means they reserve breathing for nighttime. To do this, the plant stores carbon dioxide in the form of malic acid until daylight. Then, it uses the CO2 for photosynthesis.
Because this entire process takes place during the late hours of the day when it is cooler and more humid, a cactus significantly reduces its water loss.
5 Signs Your Cactus Needs Less Water
As cacti are very slow growing, you may have invested a lot of time and effort into your little plant. Unfortunately, many of us kill our cacti with kindness, that is, by overwatering it. This is the main culprit of a struggling house cactus. Fortunately, they are pretty good at letting you know when you are doing this.
So, pay attention to these signs, and you’ll be able to save your spiky friend!
- Your cactus splits.
- Your cactus is mushy and puckered.
- Your soil stays moist for too long.
- Your cactus is starting to die in winter.
- Your cactus is turning black or brown, especially at the base.
1. Your Cactus Splits
Maybe you forgot your cactus for a while, or you went on an extended vacation. When you came back, the soil looked super dry, so you dumped a bunch of water on it. The next thing you know, the cactus has a split in its skin.
This happens when a cactus takes up too much water at one time. Since these plants are highly efficient at absorbing and storing water, they pull in more water than other house plants. While they are designed to expand during times of rain, too much expansion can be harmful. This is what causes the split.
Also, when they have been dry for too long, the plant has likely contracted, specifically to survive its arid conditions. You’ll want to reintroduce water slowly to your plant to allow it to expand and grow at its own rate, especially if it’s been a long time since its last watering!
But don’t worry! Splitting does not cause long-term damage to the plant. Cacti have adapted to repair themselves from this kind of damage by creating a callus and sealing off the area. Just continue watering lightly, and your plant should grow as usual.
To learn more about cacti splitting, check out this YouTube video by Desert Plants of Avalon.
2. Your Cactus is Mushy & Puckered
The problem with puckered succulent leaves or cacti is that it can be attributed to too little or too much water.
A healthy cactus will be plump and firm because of the water stored inside it. These stores are used as reserves for times when new water is scarce. As the cactus dries out, it will begin to tap into these reserves to survive. If it draws too much from them, the skin begins to pull inward as water volume is lost. This is a sign of too little water and usually happens at the bottom of the plant first.
Conversely, if the cactus absorbs too much water, then the storage space will run out. As water is stored in the cells of the plant, these cells will burst if too full, and the plant will literally fall apart from the inside out. This results in a puckered and mushy plant.
Therefore, you should make sure to pay attention to your watering habits to determine if you are under- or over-watering your cactus. To remedy this, ease into adding more water or decreasing watering time slowly so as not to shock the plant too much.
Do you think one of these things is happening to your plant? If you’re not sure what you should be looking for in terms of mush or puckering, check out the photos in this article from Pistils Nursery. There are good examples of what these signs usually look like.
3. Your Soil Stays Moist for Too Long
While you may be tempted to use standard potting soil or compost for your new cactus, this should be avoided. Regular potting soil is designed to hold moisture close to the plant. This is because other houseplants are not as good at quickly absorbing water as cacti.
Cacti are gluttons for water. That is, they soak up as much water as quickly as possible. This is because the soil in which these plants are found is naturally poor and arid. Any rainfall is not likely to stick around long—whether it drains by runoff or disappears by evaporation. This means the cactus needs to get it before it’s gone.
Therefore, if the soil stays wet around the roots for too long, your cactus will keep drinking it until it oversaturates itself; it doesn’t know when to stop! And worst yet, this oversaturation could lead to root rot and other problems.
- Gritty mixture (pebbles or pot shards)
Some mixes even contain:
- Coconut fibers
The necessity of these additional ingredients really depends on the type of cactus you have, so read the instructions carefully. For example, peat is useful if you live in a very arid climate. It is designed to hold moisture, but if you allow it to get too dry, it will not rehydrate well.
You can buy a commercial cactus mix or make your own, but the benefit of this mixture is that it will drain faster and encourage evaporation. Once you’ve changed the potting medium, make sure to let it dry out thoroughly between watering. And don’t forget to empty the drainage saucer if there is one!
4. Your Cactus is Starting to Die in the Winter
You may be thinking that your cactus is dying because you are currently in the coldest months of the year. While these plants do love warm temperatures and sun, since they are desert-dwellers, they are no stranger to chilly nights. So, if you keep your cactus indoors and it’s not directly near a cold window, it’s unlikely that the winter weather is causing it to die.
As with all plants, cacti go semi-dormant or dormant in the winter. Their growth slows considerably, and their soil generally does not dry out as fast. This means they generally need less water than in the summer months. Therefore, if you have kept up the same watering schedule even as the days grow shorter, you may be watering your cactus too often.
All plants, in general, need less water over the winter, and cacti are no exception. While you may water your cactus once a week in the summer (or more if you give it outside time in the hot sun), that may be too much for the winter. Try to simulate the cactus’s natural habitat.
Most plant experts recommend only watering the cactus two or three times during the entire winter season. And when you do, make sure to follow tip number one above and not give it too much water at one time!
5. Your Cactus is Turning Black or Brown
Discoloration can also be another sign of either under- or over-watering. It is essential to know the difference between different shades and textures that may appear as a result of how you water your cactus.
For a cactus that is too dry, it may be turning brown and crispy at the tips. These look like callouses or sunburns. If this is your cactus’ symptom, try giving it more water and over time, the plant will heal its damage. But make sure the soil is fully draining!
On the other hand, if the leaves or stems are turning black or dark brown, that could be a sign of root rot because of overwatering. These dark spots usually occur at the bottom of the plant or on the lower leaves/appendages. They are soggy and can even be oozing or leaky. This means that your plant has so much water that it’s now collected in the roots.
If you suspect this is the case, gently pull your succulent out of its pot and examine the root base. If the root network is expansive and looks healthy, then your plant may survive. Repot it in fresh, dry soil and decrease your watering.
If the roots look dead or blackened, then your succulent is in trouble. It is most likely that you will need to try to salvage its healthier sections in order to keep it growing well.
Not sure if your cactus is experiencing root rot or dryness? Check the photo examples from this article on Pistils Nursery to compare your plant to.
Saving Your Cactus from Overwatering
So, what if you have changed the potting medium and readjusted your watering routine, but your cactus still seems sad, and you notice continued mushy spots or dark patches? This may mean your cactus has developed some type of rot, which is slowly spreading through the rest of the plant. Plants cannot heal already rotted flesh, so if you notice these spots, it is best to remove them if at all possible.
Removing Rot from the Top
If the damage is at the top of your cactus, you have a better chance of saving it. Take a sharp, clean knife and dig out the damaged tissue gently. Allow the hole to dry out and heal over. Make sure not to water the plant from above to prevent moisture and bacteria from getting into the wound.
If you give it time, the plant should callous over, and while now looking a little scrappier, it should continue to grow and get healthier!
Removing Rot from the Roots
If you suspect root rot, this is a more difficult problem to tackle. It is possible to save the plant, but it will take extra care and even a little luck.
- Determine if any healthy roots are left. First, remove the plant from its soil and inspect the roots. If all of them are blackened, limp, or broken off, your plant may not survive. However, if any are still viable, you may try to replant it.
- Separate the dead tissue. Remove any infected tissue and all surrounding soil from the cactus.
- Wash the roots thoroughly. This will remove any remaining diseased soil or rot from around the roots.
- Repot in sterile soil. Plant the cactus in a fresh batch of potting medium, ensuring that its amount and type is suitable for your cactus. This is also an excellent time to check your pot size, making sure it’s not too large or too small.
Root a Cutting
If you determine that the roots of your cactus are no longer viable, you may still be able to root a cutting. Depending on the plant, if there is a healthy part still left, you can cut that piece off from the rest and help it grow new roots.
First, allow the cutting to callous over for a couple of days before placing it in the soil. When planting, make sure to bury it at least an inch into the medium so it can begin to root. While this process may take weeks, you should see a brand-new, healthy baby cactus that is quite similar to the parent plant!
While over-watering can be a death sentence for your little cactus, it doesn’t have to be. Paying attention to the signs above, and catching them early enough, will allow you to save your succulent just in time. If you follow these simple tips, you and your new houseplant can celebrate many great years together!