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One of the questions I’ve often run across on the internet is “Why is my cactus turning red?” And specifically in this case,” Why is my peanut cactus turning red?” The usual answer I’ve found says that it is due to stress and then goes on to talk about the things that can negatively affect your cactus. That is true since there are health problems that will cause your plant to turn red, but there are also some cases where the stress isn’t from a health problem but from overexposure to sun or cooler temperatures. If it’s not an extreme overexposure it won’t harm your cactus and the resulting redness can enhance your plant’s appearance.
Peanut cactus, Echinopsis chamaecereus, will turn red when it is under stress. Excessive sun exposure, a lack of water, and exposure to cold temperatures are some of the most common causes of stress to these plants.
What Causes Peanut Cactus Plants to Turn Red?
Several different things can cause your cactus to turn red. It is a sign that it is under some sort of stress as mentioned before. You may not know what it is in your case– that’s why you need to try to identify any potential stressors. Is it looking unhealthy? Is it subject to extreme environmental conditions? Is it getting enough water?
Some cactus plants turn red for reasons that are concerning because they might point to a health issue. Other reasons might not be alarming right now, but they still call for you to watch them and make sure they don’t become overly stressed.
Here are four common stressors that could be the reason your cactus is turning red.
1. Exposure to Sunlight Will Cause Your Cactus to Turn Red
Like other types of cacti, peanut cacti will often turn red or purplish in color when exposed to high levels of sunlight. The red pigmentation the plant makes acts like a “sunblock” to protect it from excessive sunlight. The more sunlight it receives, the darker the pigmentation.
This isn’t anything to worry too much about by itself as long as your plant isn’t getting an excessive amount of overexposure to sunlight or even burned by the sun.
Note: Sunburned plants turn white and by the time you notice that it’s white, the damage has already been done. The damaged parts of the cactus will remain white,(or bleached out) and will be permanently scarred. This happens when you don’t “harden” your plant by slowly increasing sun exposure over time. (Reference)
If your peanut cactus is turning red due to overexposure to sunlight, the simplest solution is to move the plant to where it will receive less sunlight during the day. The redness is temporary and will fade with time.
Many people, myself included, enjoy the striking appearance these plants make when they are “slightly stressed” in this manner– especially when it’s blooming at the same time.
What’s important to remember is that this stress isn’t caused by disease, and in small amounts it isn’t harmful to your cactus. If you like how your peanut cactus looks in this “slightly stressed” state just remember not to let them get stressed too much!
2. Underwatering Causes Your Cactus to Turn Red
Cactus plants are drought tolerant but they, too will suffer if they don’t receive adequate amounts of water.
Underwatering is a source of stress that will cause your plant to turn shades of red, shrivel up, and then turn brown.
This is a problem especially when they are planted in pots.
We’ve learned that our cacti in certain types of pots, such as terracotta, need to be watered more often than those planted in other types like plastic or ceramic. We have to take into account what type of pot our cacti are planted in so they won’t be underwatered.
It’s best to water your peanut cactus on a regular schedule and your schedule may vary depending on the conditions your plant is experiencing.
The type of pot it is in, whether it’s sitting on a sunny windowsill, or if it’s in indirect light will all make a difference.
Check out our other articles on this subject if you want more information about how often you need to water your cactus, how to know when your soil’s dry, or how to use a soil moisture meter and how it works.
3. Temperature Fluctuations Will Cause Your Cactus to Turn Red
While cactus plants are more tolerant of high temperatures than other houseplants, temperatures over 90 degrees may harm them. This may be another reason your peanut cactus is turning red.
Windows can concentrate the heat from the sun. When it is summer and the sun’s rays are at their strongest, it might be best to place your cactus in bright, but indirect light and out of the harsher sunlight that it would get if it were on the windowsill.
Likewise, cooler temperatures will also cause your plant to turn red. This picture is taken of a peanut cactus exposed to slightly cooler temperatures (around 55 degrees, at the lowest) for prolonged periods of time. It was also exposed to direct sunlight for at least 8 hours per day with daytime temperatures between 70-75 degrees.
The combination of exposure to full sunlight and cooler temperatures caused this cactus to develop a pinkish-red color. This coloration was only temporary in this case and did not harm the plant. If anything, it enhanced its appearance, and in addition to that – the temperature fluctuations also stimulated it to bloom.
Note: Temperature fluctuations between 50-55 degrees at night and around 70 degrees (and higher) during the day may stimulate your plant to bloom. This is not only true for Peanut cactus plants but for other types of cacti too.
Temperatures that are too low will damage your cactus, so If your plant is near an open window, on the porch, or in an unheated room, you should move your cactus to a warmer spot before the temperature drops too low.
Note: Not to confuse things too much, but some peanut cactus hybrids will turn reddish to purple in color when they go dormant during the winter. If your cactus is one of these hybrids, this could also be a reason why it is turning red.
4. Nutrient Deficiencies May Also Cause Your Cactus to Turn Red
A lack of certain nutrients may cause cactus plants to turn red and peanut cacti are no exception. They don’t usually need much fertilization to thrive, but if the soil isn’t good, the lack of nutrients will affect the health of your plant.
If you decide to fertilize your cactus, do it during the growing season and make sure your plant is receiving a balanced cactus fertilizer.
Amazon has this fertilizer which is formulated for cacti and succulents.
If you want to repot the cactus into a good, cactus soil, Amazon has several that you can choose from. Of course, you can also buy good cactus soil at a local garden center too, or make your own!
Final Observations:
Once you have determined what is causing your cactus to turn color, you can take steps to correct the situation, if needed – especially if it’s affecting the health or your plant.
If you’ve determined that your plant is healthy and there are no signs of distress, it’s probably just a natural and normal reaction to its environmental conditions or a seasonal color change (for some hybrids), and not something to worry about.