Cactus Etiolation – Signs + How to Fix

Etiolation is a condition where a plant becomes stretched, pale, and weak due to insufficient light. Since cacti are desert plants adapted to bright sunny conditions, they typically get etiolated when they don’t receive adequate amounts of light.

Light is an important source of energy for all green plants. It is used for the production of sugars from carbon dioxide and water during photosynthesis. When plants are subjected to low light conditions for an extended period, they start to elongate and stretch toward the available light. 

However, as a cactus try to maximize light absorption, it may become weak and may lose its compact, vibrant appearance. Etiolated cacti often have thinner stems and longer internodes. I noted this when my bunny ear cactus was growing long and skinny.

Signs of cactus etiolation

Cacti are incredibly hardy plants and you won’t easily tell when they are in distress. The following are signs that your cactus is etiolating:

Elongated stems

One of the most apparent signs of cactus etiolation is the spindly stems. Instead of growing compactly, the stems become stretched and appear thin and weak. However, being thin and skinny can also be a sign of overfertilizing.

Discoloration

Etiolated cacti often exhibit a paler or yellowish color. This is because the plants are not receiving enough light to produce sufficient chlorophyll, which is responsible for the green color. Cactus turning yellow can also be a sign of other issues including overwatering, underwatering, and nutrient deficiencies.

Limp growth

Due to the lack of light, etiolated cacti tend to have weaker and more fragile growth. The stems may be unable to support themselves, resulting in the cactus leaning on one side or falling over. Limp growth can also signify root rot problems, underwatering, and even physical damage.

Spacing between areoles

In etiolated cacti, the spacing between the areoles is often wider, indicating unusual elongation of the internodes or stem segments. This unusual stretching of tissues is one of the sure ways to identify cactus etiolation.

Reduced spines

Etiolated cacti may have fewer and smaller spines compared to healthy ones. Lack of light affects the production of sugars needed for the development and growth of spines and other tissues.

Stunted growth

Etiolated succulents may experience slow or stunted growth due to a lack of energy. Inadequate light restricts photosynthesis, which hampers the plant’s ability to synthesize sugars and grow properly. The affected plant may eventually wilt and die off.

Cactus not blooming

Cacti have evolved to grow in arid environments with bright sunlights. Adequate light exposure enables them to produce enough energy to support flower bud formation. Therefore, a cactus that is not blooming is likely to be experiencing shortage in light supply.

Note: Some cacti naturally have elongated stems, including many columnar cacti. However, if you observe a combination of the above signs in a cactus that typically has a more compact growth habit, it is likely experiencing etiolation.

How to fix etiolated cactus

There are various steps you can take to help the etiolated cactus recover and regain its normal shape. 

1. Place the cactus in a location where it can receive bright, indirect sunlight for at least 6-8 hours a day. A south-facing window is usually the best spot. If natural light is limited, supplement it with artificial grow lights. Position the lights close to the cactus to provide adequate light intensity.
2. If your cactus has been in low-light conditions for an extended period, sudden exposure to intense light can shock the plant. Gradually acclimate it to brighter light by initially placing it in a partially shaded area and then gradually increasing the light exposure over a few weeks.
3. If your cactus has elongated stems, you can prune them to encourage new growth and a more compact shape. Use a clean, sharp knife or pruning shears to make clean cuts just above a joint or node. 
4. While trying to save an etiolated cactus, ensure you are watering it correctly. Overwatering the cactus can lead to root rot, which can further weaken the plant. Water the cactus only when the soil is completely dry, and make sure the pot has drainage holes to prevent waterlogging.
5. Keep the cactus in a warm temperature between 65-85°F (18-29°C) during the day and slightly cooler at night. Avoid exposing it to cold drafts or sudden temperature changes and overly humid conditions.
6. Once your cactus starts showing signs of recovery and new growth, you can apply a balanced cactus fertilizer as directed on the package label. Fertilize during the growing season (spring and summer) to provide essential nutrients that aid in healthy growth.

Remember that it takes time for an etiolated cactus to recover and regain its compact shape. Be patient and consistent with the care you provide, and over time, you should see improvement. If you don’t see any changes in about three months, then repot your cactus in a fresh soil mix.

Final Thought

It’s important to note that cacti are generally hardy plants and can tolerate some degree of etiolation. However, prolonged low-light conditions can weaken the plant and make it more susceptible to disease and pests.

To prevent or reverse cactus etiolation, it’s important to provide the plant with sufficient light. Place the cactus in a well-lit area, preferably near a window with bright, indirect sunlight. If natural light is limited, you can supplement it with artificial grow lights specifically designed for the plant.

References

Plant Phototropism – National Library of Medicine

De-etiolation – Berry College

Tips for Growing Houseplants – The University of Maine