Cacti are super hardy plants known to store water in their succulent stem. They prefer sunny conditions and well-draining soil. Their minimal watering and fertilizer needs make them a great addition to any garden.
If your cactus is leaning and falling over, it could indicate poor or directional lighting, root damage, improper potting, and pest or disease problem.
Why is my cactus leaning on one side?
The following are the main reasons why a cactus is leaning and falling over:
1. Poor or directional lighting
Like other plants, cacti need sunlight to make their own food through photosynthesis. Without sufficient light, plants weaken and lean towards the side where light is strongest.
This phenomenon where plants lean towards a source of light is called phototropism. It was discovered by Charles Darwin, who reported his experimental findings in a book published in 1880, The Power of Movement in Plants.
He explained that plants have light-sensitive special cells at their growing tips. These cells detect a difference in light intensity between the bright and dim sides of the plant.
In directional light, the cells on the dim side grow more but weaker, unlike the side with bright light, where they grow slowly and stronger.
How to fix
Cactus should be grown in places that receive enough sunlight. Further, turn the plant whenever you water it if the light comes from only one side. Alternatively, set artificial lights on the shady side of the plant. This should keep your plant growing symmetrically healthy.
2. Damaged roots
Roots are important in anchoring a plant in the soil. More importantly, they are the lifeline of a plant, taking up the air, water, and nutrients from the soil. Roots can get damaged by pests or excess moisture in the soil.
The excess moisture in the soil limits the roots from taking up the air, causing them to suffocate and die. Christmas cactus root rot, for example, is caused by poor draining soil or overwatering, and it can be difficult to detect.
How to fix
Signs of cactus root rot may include yellowing or wilting of the plant. You may also notice a soft or mushy texture to the stem or roots and a foul odor. If left untreated, the entire plant may eventually die.
Stop watering the plant if you have been overzealously doing it. If the cactus is leaning on one side, inset a moss pole in the soil and lightly tie the cactus to it. Let the soil dry out completely before watering again.
If your cactus doesn’t seem to recover, remove it from the soil and inspect the roots. If they are badly damaged, cut them off using a sterilized knife and repot the plant in fresh soil.
3. Improper potting
Most cactus plants prefer lightweight, well-draining soil. If you did not plant deep enough or compact the soil around the root ball, then it results in the cactus falling over when tall or leaning on one side. This happens as a result of topside weight overwhelming the support at the base.
It is also important to note that cacti also like small quarters. The plant tends to root more and establish faster when the pot is small. Using oversized pot results in weak roots that cannot support the plant.
How to fix
Support the cactus with a peat moss pole and top the soil with your preferred succulent potting mix or sand. Water lightly and place the plant in a sunny spot. The plant should regain its support in a matter of weeks.
When repotting or transplanting a cactus, use a pot 1½ times as wide as the root ball or stem. An unglazed terracotta clay pot will be suitable as it dries out more quickly. Fill around the root ball with a fast-draining soil mix to enhance the plant support.
Water your cactus only when the soil feels dry to the touch. Frequent watering may loosen the soil or cause root rot, contributing to the leaning of a cactus.
4. Pest insect problems
Pests are known to damage a cactus plant’s stems and roots, causing it to lose stability. Mealybugs, aphids, and spider mites suck sap from the pant and, as a result, create open wounds through which water or pathogens enter the plant.
In time, you’ll find that your cactus is getting squishy, yellow, and shriveled due to the pest problem.
How to Fix
Regularly inspect the plant for pests, although it may be difficult to spot them when they are hidden in the soil. To get rid of mealybugs on cacti and other insect pests, wash the plant with a strong stream of lukewarm water or clean the plant with a cotton swab dipped in rubbing alcohol.
5. Insufficient moisture
Watering is one of the important aspects of growing plants. Water is useful in carrying dissolved sugars and nutrients across plant tissues. So without watering, the cactus plant cannot support its own weight; it physically weakens and falls over.
In extreme cases of underwatering, the cactus root cells get dehydrated and die. This causes the entire root system to rot and fall apart, and the rest of the plant will follow suit.
How to fix
Saving an underwatered cactus is the easiest as compared to an overwatered one. Start by misting the plant every other day without drenching the soil. It should take about one week for the plant to recover from dehydration.
Now water your plants heavily and let the excess water drain from the pot through the drainage holes.
If the plant won’t recover, it signifies severe root damage. Removing the damaged roots and repotting the cactus in fresh soil is the only option. While there is no conclusive way to determine how often to water your cactus, it is important to water when the soil feels dry.
There is no beauty and vigor in a leaning cactus. The plant may be undergoing a problem that needs your attention. Look into its growth conditions and fix any underlying problem causing your cactus to lean or fall over. Inspect for pests, check soil moisture, and ensure the plant gets sunlight.
- References: University of Minnesota Extension: Cacti and Succulents
- University of Nebraska Extension: Succulent Care
My name is Diane M Lewik, and I am the founder of this website. I am a degree holder in plant biology from the University of California – Berkeley. Over years, I have cultivated a vast collection of succulents and I have learned a great deal about how to grow and care for these unique plants.