Why is My Cactus Shrinking?

Cacti are easy to grow and care for, and despite their prickly thorns, they are lovely to look at. The plants belong to the family Cactaceae, which has at least 1,750 species of the order Caryophyllales. The word ‘cactus’ comes from the ancient Greek word ‘kaktos’, a spiny plant. In this article, you can get to know the reasons cacti are prone to shrinking. 

Why is my cactus shrinking?

Here are some possible reasons your cactus is shrinking:

1. There is too much light. 

Cacti prefer sunlight and are usually exposed to a lot of sunlight throughout their lifetime, but if they are grown in cold areas they will naturally adapt to that environment. In this case, do not expose cacti to sudden bright light, as they will easily burn. If you are living in a cold country, allow your cacti to go dormant during the wintertime. 

Once the winter season is over, gradually re-introduce the cacti to bright light. Place them in bright light, but create shade using gauze or other semi-transparent material. As summer approaches, remove parts of the cloth to allow more exposure to sunlight. 

Avoid sudden changes in light or temperature, such as drafts or air conditioning, as this is bad for the plants and can cause loss of spikes, shrinking and burns. 

2. It could be due to overwatering or rotting.

Cacti may also shrink due to overwatering, as this leads to root rot that spreads and causes shrinking and softening of parts of the plant. If you notice that the plants have soft stems and have lost their shape, it could mean they are rotting. You may also notice yellowish coloration at the base and around the stems. 

3. There is not enough light.

Cacti cannot survive if they do not have access to sunlight for a certain time. These plants tend to start leaning and display elongated growth, also known as etiolation. They will not be able to photosynthesize without light, and their metabolic processes will cease. Cacti prefer bright and indirect light, although if you are in a cold country your plants may require full sun. 

See to it that your cactus plants are placed in an area with available sunlight during winter dormancy. Make sure they are in cool conditions, about 54 to 59 degrees Fahrenheit, or they will start thinning and growing. If cactus plants are kept in dark, warm conditions, they will start to die. 

Once winter is over, let your cacti acclimatize to the stronger sun again, but be sure to shade them in the first few days. If you notice that they are shrinking and have a bad smell or any yellowing, it could mean they are dead despite the roots looking normal. This could be due to lack of light, overwatering, or being kept in warm and dark conditions during winter.  

4. They could be under-watered. 

Cactus plants can also shrink if they are underwatered, which could become a long-term issue. They usually prefer fast-draining soil to dry out between waterings. It is ideal to use a soil meter to check the moisture levels of the soil. 

Plant experts recommend watering your cacti once every four to six weeks, but only lightly during winter dormancy. Some cactus owners won’t water at all, but it is recommended to water just slightly since transpiration still occurs during dormancy. During this time, cactus plants are likely to shrink but will bounce back to their normal health once normal watering schedules resume. 

Aside from those mentioned above, other reasons that could affect the condition of your cactus plants may include environmental factors like droughts. Coccid scales or soft scales, as well as other types of insects, could also be a reason for your cactus shrinking. These insects feed on the juices or sap of the cactus plants and result in shriveling and shrinking. Cactus longhorn beetles also feed on cacti and may dig into cactus roots, making the plants collapse and shrink. 

Fungal diseases can also shrink cactus plants and are noticeable as a type of rot on the plants’ surface. Overwatering cacti could cause root rot and pythium rot. Cacti with fungal infections may shrink even before the fungus becomes obvious on the outside. To prevent this, plant cacti in pots with drainage holes and water the plants just enough to keep them from shrinking because of too little water. 


Cacti are hardy plants that do not need much water to survive. However, they may be prone to shrinking due to too much light or overwatering. Shrinking could also be due to too little light or underwatering. Environmental factors like droughts, as well as insect damage and fungal infections, could also be the reason your cactus is shrinking. 

Image: istockphoto.com / insonnia