You look to the window at your cactus one morning to find it turning red. Panicking, you wonder if this means you have an unhealthy cactus. You might look at red as another shade of pink, and the reasons for them changing colors are similar. I had previously written an article on “Why is My Cactus Turning Pink?” Without further ado, let’s dive into the reasons why a cactus might turn red.
Why is my cactus turning red? A cactus will sometimes turn red because of too much sunlight or too much stress. Also, some cactus, such as the Gymnocalycium mihanovichii, have a red appearance anyhow. Stress can bring out a red appearance, but it doesn’t mean the cactus is unhealthy.
Stress on the Cactus
If a cactus feels stressed, this can bring out the red pigment. A red cactus doesn’t necessarily mean that the cactus is unhealthy, however. The common stresses to a cactus include:
- Less water
- Less heat or more heat
- Less nutrient-rich soil
- No fertilizer
People stress plants like cactus to make them more colorful. In some cases, the red might be desirable. You might do this with cactus to turn its colors because it remains perfectly healthy even when red. When you bring water and fertilizer back to it, the cactus will usually return to its normal color. Don’t do this for too long, or it could have a negative impact.
Mild Blush or Heavy Red?
A slightly red hue on a cactus indicates stress, and it looks beautiful. A deep or heavy red doesn’t always look so attractive, and you might return the cactus’s stress levels to normal as a way of dealing with it.
Does Stress Harm the Plant?
No, when a cactus turns red from stress, this does not harm the plant in most cases. Some plant enthusiasts will even do this to make the plant more colorful. With cactus, it doesn’t look as pretty, but you might try it for a fun experiment. Once the environmental stressors stop, the cactus returns to its normal color. Stress doesn’t harm the cactus, and in fact, they were programmed to do this through evolution.
Organic Matter in the Soil
One thing to understand with most cactus is that they don’t like organic matter. Look at the desert environment that they inhabit, and you will understand. You might turn the cactus red in some cases if you make the soil too rich.
Red Cactus Spines vs Red Cactus
Important to note, cactus spines turning red signal a natural part of the maturing process. That differs greatly from the cactus itself turning red. If you’d like to learn more about red cactus spines, I wrote an in-depth article here.
In general, red cactus spines will be even less worrisome than a red cactus because it shows that the cactus has come of age. A red cactus usually doesn’t mean that you have an unhealthy cactus, but you should still remain alert to what might be causing your cactus to feel stressed.
Root Rot
You have cases where root rot could turn your cactus red. In most cases, a cactus turning read will be benign, but you should check for telltale signs. Have you overwatered your cactus? Do you use sandy soil? Overwatering can cause root rot and sandy soil ensures that the water doesn’t hold in the soil. Beware of a musty or sour smell from the soil.
Wilting or where the plant turns red or pink could indicate root rot in some cases. You shouldn’t disregard this sign entirely because it could mean that the cactus feels stressed. If you discover root rot, you should replant the cactus into a new soil and pot. After replanting it, you will want to avoid watering it for between two to three weeks to eliminate the root rot. Hoffman 10404 Organic Cactus and Succulent Soil Mix is the perfect blend of soil, and it uses a professional formula to work with both jungle and desert cacti.
Nutrient Deficiency
In some cases, red or purple cactus signals a lack of magnesium in the soil. Pay attention to the overall look of the plant. Along with discoloration, if the cactus has wilting, this signals a magnesium deficiency. Nutrient deficiency especially happens over the winter season when cold weather slows the nutrient intake of the plant.
You might add Epsom salts to the soil to correct a magnesium deficiency. Take 8 tablespoons of Epsom salts into 2 1/2 gallons of water. Next, add 1 drop of dishwashing soap. Continue to apply the mixture over the course of two weeks until the color of the cactus returns to its normal green.
Why Does a Cactus Turn Red?
When under stress, a cactus might turn red or pink. Experts call these pigments carotenoids and anthocyanins. Carotenoids and anthocyanins can also be found in fruits high in antioxidants. The antioxidants provide protection for the cactus in its natural environment to handle extreme heat, cold and drought.
While the beautiful colors brought out from stressing a cactus look unusual and stunning, you have to look at this as a baby crying. Don’t let it progress too far. The cactus is protecting itself when it turns red or pink. For that reason, you want to correct the problem eventually to ensure that the discoloration doesn’t progress into further problems for the cactus. I found this book “Cactus (Botanical)” an excellent read on the fascinating and sometimes contradictory world of cactuses.
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