Cacti are a plant collector’s delight due to their miniature sizes and shapes. They are great indoor plants and very easy to care for, as they can thrive despite having just enough moisture in the soil. However, they are also prone to disease and may turn yellow for various reasons.
Cactus Turning Yellow: Common Reasons
These are the common reasons cactus plants turn yellow:
1. They are either overwatered or underwatered.
Cacti are hardy desert plants, but they also need water to thrive. They should be watered at least once a week to stay healthy. They reserve some of the water in their water storage cells located in their stems. However, once they have used up the reserved water they may look shriveled and will start to turn yellow from the base upward.
Solution: Water your plants often and use a stick or your finger to check if they need more water. If the stick comes out dry from the soil it means you have to water your plants again. Overwatering could prevent proper aeration, and cactus plants turn yellow when air does not get to the roots. It can also cause root rot, so you should only water cactus plants about once a week.
2. There is insufficient light.
Adequate sunlight is essential to the growth and survival of cacti. Insufficient light could lead to etiolation, a process whereby plants grown without adequate sunlight grow smaller leaves and extended stems in search of light. Some of the plant parts could turn yellow due to insufficient light.
Solution: Place the cactus plants where there is adequate sunlight, like on a windowsill, but make sure the light is just enough, to prevent scorching. Yellowing may also be due to sunburn, even though cacti are hardy desert plants. Some varieties only need partial light and store-bought cacti are not meant to be exposed to bright light. If the plants turn yellow from the top, provide partial shade so they can recover.
3. The soil type is incorrect.
Cactus plants thrive in areas where there is sandy soil that properly drains the excess water. For your indoor cactus plants, make sure you are purchasing the right type of soil, since some florists tend to use clay soil which retains water. Excess water could result in root rot and nutrients will not be transported from the soil. Your cactus plants will start to turn yellow.
Solution: Mix sandy soil into the pots to improve the drainage. Make sure there are drainage holes at the bottom of your planters to avoid stagnant water in the soil.
4. There is a pest infestation.
Pests such as mealybugs, spider mites and fungus gnats tend to invade cactus plants and other succulents because of their juicy sap. They leave scars and blemishes on the plants that could cause yellowing.
Solution: Eradicate these pests by spraying some insecticide on your plants. You may also opt for safe alternatives like rubbing alcohol, liquid soap and neem oil.
5. Due to inadequate nutrients.
Cactus plants may also turn yellow because of inadequate nutrients. When plants cannot absorb nutrients from the roots, they tend to change color and become malnourished. The culprit is usually root rot or harmful bacteria.
Solution: Check the roots of your plants to see if they can still be saved. Scrape off rotten roots and replant the cactus in fresh soil. You may add manure or compost to boost the nutrients in the soil.
Cacti may also turn yellow due to stress, such as when their pots are too small. Place the plants in bigger pots and invest in proper well-draining soil as well.
Why is my cactus turning brown?
Cactus plants may also turn brown. This is mainly due to corking, and happens naturally when the plants mature. It starts from the base of the plant where it meets the soil, and moves slowly upward or may stay in one spot. Corking gives cacti a woody appearance, but they are generally firm to the touch and healthy.
Cactus plants that are brown but also soft to the touch or mushy could be rotting or have diseases. This usually happens when the plants’ soil is constantly wet, since rot settles from the roots and spreads to other plant parts.
Fungal diseases and pest infestation could also turn the plants brown. The discoloration happens in various parts of the plant and they become soft and mushy.
Conclusion
Cactus plants add character and aesthetic beauty to homes and offices. While they are hardy plants like other succulents, they are also prone to disease and other issues which could make them yellow. The reason may be due to overwatering or underwatering, or inadequate sunlight. It may also be due to pest infestation, stress or inadequate nutrients.
Image: istockphoto.com / Dmitriy Sidor