Why Is My Cactus Turning Yellow? 9 Reasons and Fixes

There are several reasons for your cactus turning to yellow color. These plants require an arid environment to thrive. When the plant gets more stress, it produces vibrant colors. If you are searching, how do I save my yellow cactus? This is the guide for you.

Cacti require bright sunlight all day (around 6 hours) to make it compact size. However, some varieties prefer partial shade. Which means they can grow low light. For instance, scarlet ball, crown cactus. In some situations, you may notice that your cactus turns brown. All these sudden cactus plant color changes are a big issue. Turning the cactus purple is an entirely different scenario. 

There can be several reasons for cactus yellowing or brown. Without checking the plant and its environmental conditions, it is hard to mention the exact issue. In this post, I will mention the most common reasons for cactus turning yellow and brown colors. 

In contrast, cactus plants turn yellow is the insufficient bright light, sunburn, overwatering, underwatering, pest inflection, wrong propagation time, lack of nutrients, or even improper soil mix. Therefore you have to check the exact reason closely.

Reasons for cacti turn yellow and how to save.

Low sunlight.

Cacti require adequate bright sunlight all day to produce their vibrant colors and compact shape. Generally, most of this family plant needs around 4 to 6 hours of bright sunlight. Depending on the species, its light requirement different. When it is under partial or inadequate light, the cactus turning yellow at the top. Therefore gradually increase light to observe its color change behavior. You may experience such an issue when growing cactus indoor with low light.

Sunburn.

Cactus turns yellow from top to bottom; it is likely to be sunburn. Early symptoms are the development of yellowish color patches on the plant. This is due to the plant being exposed to high-intensity sunlight and high temperature for a longer time. Although cactus is a sun-loving plant, some varieties prefer partial shade. All cactus species do not require too much bright sunlight. The best thing is gradually introducing the light to the plant to identify the right amount of light. If the plant suddenly changes its color from green to yellow, it is too much light. While growing cacti outdoor, you may experience this issue. Sunburn can quickly identify the cactus yellowing at top and shriveling the plant.

Improper Soil Mix. 

Cactus need a well-drained soil mix as its growing medium. If the potting soil kept too much moisture/waterlogging, it could rot the root. Root rot’s early symptoms are cacti turns yellowish color. Regular ready-made potting mix is not a good option for cactus. When using a regular potting mix, you have to add approximately ½ part inorganic materials like the gritty mix, perlite. You can read more about homemade cactus soil mix in my previous post. 

Overwatering.

Since the cactus is a desert plant, it does not require regular watering. Overwatering can rot cactus roots and stems. The main symptom of cactus rot is, cactus turning yellow at base. Even if you have good drain soil, you do not need regular watering. These arid plants store water on their stem, pads, roots to use in droughts. It does not necessarily mean that they do not require water for more extended periods. In hot summer, it requires an adequate watering pattern. Always check the soil dryness before water cactus plants. Read more about how to water cacti.

Underwatering.

Lack of water can harm cactus plants. These plants store water on stems and roots to use in droughts. Cactus turn yellow due to continued lack of water. When the plant use stored water, it becomes soft and wrinkled. Always water cactus once the soil is completely dry.

Pest Inflection. 

Bug inflections can also change cactus color. Some of the common pests are mealy bugs, scale, spider mites. These tiny bugs sucking plant juice and result plant wrinkled, shriveled, and turn the plant yellowish. Severe infestations can kill cactus. Once you identify the cactus pest inflection, immediately quarantine the infected plant. Then try to wash the bugs away from the plant and use 70% isopropyl alcohol spray to bug colony.

Repot right time. 

In the winter season, cactus hibernate/dormant. Therefore you have to report or propagate cactus in spring or summer. Do not propagate in the late autumn or winter season. If you repot or propagate cactus in the winter season, there is a possibility of getting rot.

Lack of nutrients.

Cacti require very little regular maintenance. These plants are not heavy fertilizer feeders. Therefore most gardeners do not use fertilizer while planting them. Cactus nutrient deficiency can change the plant color. You can quickly fix the nutrient deficiency in cactus by using high phosphorus contains slow-releasing fertilizer. Moreover, adding a few organic fertilizers like compost to the potting mix also beneficial. Fertilize once a year (spring, summer, or fall).

pH Imbalance Cacti soil.

Cactus thrive in the slightly acidic soil mix. When the potting mix pH level change over time, cactus yellowing on new growth. These plants prefer 5pH to 6.5pH level soil. Even if the potting mix has enough nutrients, plants face difficulty while absorbing the nutrients.

Recommended reading: Make Own Cactus Soil Mix Recipe | Aerated, Fast Draining Soil.

Common Q&A.

What nutrients do Cactus need?

Cactus mainly require low nitrogen and high phosphorus high fertilizer, for the flowering plants need potassium to develop flowers. Slow releasing fertilizer is the best solution. 

How do you fix the nutrient deficiency in Cacti?

Slow releasing fertilizer is one of the good solutions to nutrient deficiencies in cactus plants. Moreover, you can use organic compost. Adding 20% of nutrient-rich compost to potting mix beneficial to plant development. 

How do you fix yellow cactus?

There could be many reasons cactus plants turn yellow. Some of the reasons are low light, sunburn, overwatering, underwatering, pest inflection, wrong propagation time, lack of nutrients, or improper soil mix. We can easily save yellow cactus by applying the following methods. 

1. Stem cutting. You can cut the rotted part away and plant the healthy part in the proper soil mix. Stem cutting propagation is an excellent solution to save the dying Cactus.
2. Change the watering pattern. Over or under-watering is an issue. Once you identify your plant is overwatered, cut the watering schedule. Water only when the soil completely dries. If the plant is underwatered, gradually increase the watering pattern subject to the soil dryness.
3. Gradually adjust the sunlight. Depending on the situation, you have to change the sunlight if your plant in a shaded place moves it to a partial shade. Suppose the cacti in the full sunlight area move them to a partial shade place. If you do not have the option to provide enough bright light, you can use artificial grow lights.
4. Artificial grow lights. While growing cacti indoor, if there are not enough bright lights, it is better to use artificial lights. Full-spectrum grow lights provide light similar to natural sunshine. If there’s no option to increase the bright light, you have to provide artificial light.
5. Change the potting soil. If the potting mix waterlogging immediately changes the soil. Mix more inorganic materials like perlite or pumice, gritty mix, or coarse sand to make it lose and well drain. It is useful to introduce charcoal cactus soil mixture to help prevent root rot.
6. Rotate the plants periodically. When the cactus receives bright light from a single direction, the plant must rotate regularly. For instance, plants close to a window. Changing the plant position is an essential practice when growing cacti indoors. Every 3-4 days, rotate the plant around 180° degrees.
7. Clear stem and leaf Dirt & Dust. Cactus does not have true leaves. The cacti use the stem for photosynthesis. Therefore you have to ensure that its stem clean and clear. When its stems cover dust, and dirt plants do not receive enough sunlight.
8. Let the plant Dry. When you notice a root rot, pull the plant from the soil, let its root air dry for several days ( around two days), and replant it in a cactus soil mix.
9. Use Low Nitrogen Fertilizer. Cactus can survive without using any fertilizer. Use less nitrogen slow-releasing fertilizer. The ideal fertilizer ratio is high phosphorous (P) and potassium (K). These two nutrients ensure plant root growth, flowering, and overall plant development.
10. Control Pests & Insects.The common bugs are mealy bugs, scale, spider mites. Once you identify any of these pests, wash them away using a water spray. Alternatively, you can use 70% isopropyl alcohol spray as a pesticide against these insects. Spray isopropyl alcohol directly to an insect colony.