Cactus is well-known for being a hardy, easy-care, and durable succulent. However, it can be a thorny day when you notice your cactus is turning pink. Is your plant dying or trying to tell you something is wrong?
Your cactus often turns pink in response to environmental stresses. The most common stressors include sudden temperature changes, nutrient deficiency, improper watering, root rot, and too much sunlight. In some cactus species, this is perfectly normal and your plant is just acclimatizing.
Read on to find out all potential causes and what you can do to fix your pink cactus.
Sure, cacti are sun-loving plants. However, an indoor cactus can be prone to sunburns when exposed to too much direct sunlight.
Your cactus may be on the windowsill because glass intensifies sunrays. The sunburns will be especially severe if you parked your plant on or very close to a south-facing window.
If you’re transitioning your cactus outdoors, make sure to do it in small phases. Sudden changes in light intensity will stress your plant, which will respond by turning pinkish.
You must move your cactus away from intense direct sunlight. Put it in a spot where it’ll receive a daily dose of at least six hours of bright, indirect light. A north-facing or west-facing window would be ideal.
Too Much Heat
Your cactus may turn pink due to excessive heat. This is particularly the case if the heat is linked to excess direct or unfiltered sunlight.
This occurs in two ways. First, your cactus may respond to the heat stress by producing protective anthocyanins, which is a pink to purple pigment.
Secondly, extreme heat may scorch your cactus, causing tissue damage. This prevents your plant from absorbing photosynthesis-important UV sun rays — hence the discoloration.
Overheated roots may also cause your cactus to turn reddish-purple.
Move your cactus away from the source of heat. Be it direct sun, heating vent, or radiator.
Your cactus isn’t too finicky about watering, but it needs water, nonetheless. It may turn pink due to both too much and too little water.
When underwatering is the issue, your plant will turn pinkish or purple before drying to a dull, crispy brown. You may notice wrinkling or curling near the base of your cactus.
Overwatering your cactus is a surefire recipe for root rot. It’ll turn yellow at first then take on a brown, pink, or purple cast. Scabbing (developing rusty or corky areas) also indicates overwatering.
Eventually, your cactus will turn soft, mushy, and die.
- Water your underwatered cactus thoroughly and deeply.
- For an overwatered cactus, remove any diseased roots, treat healthy ones with fungicides, and repot with fresh soil.
- You must let the top 2-3″ of soil dry out completely between drinks.
Cacti often turn pink when they lack major nutrients, especially phosphorus. Your cactus needs phosphorus to make nucleic acids, sugars, and energy.
Pink cactus may also result from magnesium or nitrogen deficiency. Yellowing, wilting, or paling are other signs of a nutrient-lacking cactus.
Spent potting mix, poor drainage, and too much fertilizer often cause nutrient deficiency. Also, check for root damage due to infestation.
Top or repot with fresh, high-quality fertile soil if the current soil is already spent. You can also fertilize your cactus with a half-strength houseplant fertilizer during the high-growth season. (Source: University of Minnesota)
For magnesium deficiency, you can use Epsom salt.
Cactus thrives in fast-draining, well-aerated soil. Poor drainage makes it harder for the roots to breathe and absorb nutrients.
Unfortunately, this poorly drained soil also tends to get waterlogged and then cause root rot. If they stay wet for longer, your cactus roots will suffocate and die.
As such, your plant is unable to absorb water and nutrients like phosphorus, nitrogen & magnesium, resulting in foliage turning pink or purple.
If root rot has set in, prune away dead or diseased roots. Don’t forget to reduce foliage for better recovery.
Otherwise, just repot your plant is fresh, cactus potting mix.
Low light is another leading cause of cactus turning pink. Your cactus usually produces more anthocyanins due to stress from inadequate light. This purple pigment outshines green chlorophyll, giving your cactus that pinkish look.
Although some cactus species can tolerate low light, most of them will lose their vibrant green sheen if they can’t get enough sunlight for photosynthesis. You may also notice some yellow and/or whiteish areas.
Again, the best solution is to put your cactus near a spot where it’ll get enough bright, indirect light. Some species of cactus do well in part sun, part shadow.
While some cactus species (such as prickly pears) are cold-hardy, they generally hate extreme drops in temperature below 50 °F (10 °C). This will lead to temperature stress and your cactus will turn to discoloration in response.
To prevent cold temperature-induced pinking of your cactus, place your plant in a room with ideal temperatures. Your cactus will be happiest in a temp range of 70-80 °F (21-27 °C).
During the dormancy phase of your cactus, keep temperatures at 45-55 °F (7-13 °C). Also, move it away from sources of cold drafts, such as exit doors, uninsulated windows, and HVAC vents.
Pest and Diseases
A pink cactus can be a telltale sign of pest infestation or disease.
- Cactus cyst: The most common discoloration-inducing disease is a cactus cyst (caused by Cactodera cacti which are usually found in infected soil). If you check the soil, you’ll find small, spherical nodules. Other signs include wilting and stunted growth.
- Fungal root and stem rot: these infections that may turn your cactus pink are caused by fungi like Dreschlera. Lookout for mushy parts, rotting smell, and sickly look.
- Spider mites: These pests suck sap from softer parts of the cactus. Watch out for small mite webs, especially on the underside of the foliage. You may also see brown spots with a yellow halo.
- Scales: This is another kind of insect that sucks the sap out of tender parts. They also leave unsightly brown spots, while some areas may turn pinkish or purple.
You must isolate and treat the affected cactus immediately. Trim off diseased or affected parts to prevent further spread.
Now you know all the possible reason for your cactus turning pink and how to revive it.