The reason for a cactus turning yellow is usually because of overwatering. Cacti are drought resistant plants that do not tolerate consistently damp soil. If the soil is too damp and does not dry out between bouts of watering, the cacti develops root rot which causes the cactus to turn yellow and soft.
Cacti turn yellow in Winter because of overwatering and temperatures lower then 40°F. Cacti are dormant during Winter, which significantly reduces their demand for water and leaves them at a higher risk of root rot due to overwatering.
Cacti can turn yellow at the top due to sun burn if they are moved from an area of relative shade to full sun without time to acclimatize to a higher light intensity.
Cacti can also turn yellow and wrinkled if they are not water often enough or watered too lightly.
To save a yellowing cactus it is important to replicate the conditions of its native environment by watering when the soil has dried out, ensuring a temperature range of 55°F to 85°F (13°C to 29°C) and removing any diseased roots with a sterile pair of pruners.
Keep reading to learn what is causing your cactus to turn yellow and how to implement the solutions to save your yellowing cactus…
Cactus Turning Yellow, Soft and Mushy
The reason for a cactus turning yellow and soft is because overwatering and cold temperatures. Cacti are drought resistant plants that need the soil to dry out between each watering and prefer a temperature range of 55°F to 85°F. If the soil is too damp and cold the cactus turns yellow and mushy.
Cactus’s are drought resistant plants that have specifically adapted to thriving in warm and dry environments with well draining soils and infrequent rainfall.
To grow a cactus successfully and to avoid the leaves turning yellow and brown, it is important to recreate the conditions of the native environment by planting cacti in gritty, well draining potting soil and only watering when the soil around the roots has dried out.
If the soil is consistently damp around the roots of the cactus, due to overwatering or slow draining soils, parts of the cactus can turn yellow and brown with a soft mushy texture which can indicate root rot.
Saucers, trays and decorative outer pots can also prevent water from escaping from the pot and cause it to pool around the roots which can be the cause of root rot and result in a yellow, mushy cactus.
How to Save a Cactus Turning Yellow, Soft and Mushy
- Scale back how often you water your cactus. If you are watering your cactus more often then once per week, then this is the reason your cactus is turning yellow and soft. Cactus plants should only be watered when the soil around their roots has dried out completely. This typically takes around 14 days, but can vary according to the size of the pot, the climate and the drainage of the soil.
- Lift the cactus out of the pot, remove the soil and inspect the roots for root rot. Healthy roots feel firm, thick and look a whitish color (or slightly brown due to the potting soil) whereas diseased roots are mushy and rotten with a bad smell and brown in color. Use a sterile pair of pruners to cut back any diseased roots back to healthy growth. Wipe the blades of your pruners with a cloth soaked in disinfectant between each cut to prevent potentially spreading pathogens from diseased roots to otherwise healthy roots.
- Repot of the cactus in new soil. Specially pot the cactus in specially formulated ‘succulent and cacti soil’ which replicates the gritty, well draining soil of the cactus’s native environment. Normal potting soil holds onto moisture too long for the drought adapted cactus to tolerate and is often the reason for a cactus turning yellow. ‘Succulent and cactus’ soil’ significantly reduces the risk of root rot from overwatering and it is available in garden stores or online for a reasonable price.
- Always plant a cactus in a pot with drainage holes in the base and empty saucers and trays regularly. Cacti can be planted in a wide variety of pots as long as the pot has drainage holes in the base, to allow excess water to drain effectively to prevent root rot. Terracotta or clay pots are best as they have a porous structure that allows the potting soil to dry out more evenly which suits the cactus preference for dryer conditions. Plant cacti in pots proportionate to their size as larger pots contain more soil and therefore a greater capacity for holding moisture which slows the rate at which the soil dries out and increases the risk of root rot.
To establish when the cacti potting soil has dried out around the roots, feel the soil as the bottom of the pot through the drainage hole in the base of the pot.
If the soil feels damp, then delay watering the cactus for a few days. When the soil starts to feel dry, this is the perfect time to water your cactus.
Watering your cactus when the soil has dried out, effectively emulates the natural conditions of -rainfall followed by drought- cycle to which the cactus is specially adapted.
Once you have addressed the causes of why your cactus is turning yellow, soft and mushy, and implemented the appropriate watering schedule, the the cactus can starts to recover.
However if the root rot is extensive it can be very difficult for the cacti to recover and the best option is to propagate your cactus from any remaining healthy growth.
Cutting any yellow, soft and mushy sections of your cactus off with a sterile pair of pruners also helps to prevent the rot from spreading.
Almost all houseplant cactus plants propagate easily from pads, offshoots and even healthy portions of the stem.
Watch this helpful YouTube video, for how to easily propagate cactus plant from pads, cuttings and offshoots to save your cactus:
Cactus Turning Yellow in Winter
The reason for a cactus turning yellow in Winter is usually because of root rot due to overwatering. In Winter cacti are dormant and stop growing due to low temperature and less light which reduces their demand for water which makes them vulnerable to overwatering. Overwatered cacti turn yellow and mushy in Winter.
Cacti are more susceptible to overwatering in Winter because:
- Cacti are dormant with fewer hours of light and cool temperatures and they practically stop growing during Winter, so they do not need as much water. During Winter the roots do not draw up moisture which means the soil stays moist for longer and the damp soil promotes the conditions for root rot.
- With cooler temperatures and less light, the rate at which the soil dries, slows down considerably which means the soil around the roots stays damp for longer and increases the risk of root rot which turns the cacti yellow.
How to Save a Cactus That is Turning Yellow in Winter
- Scale back how often you water cacti in the Winter. Exactly how often to water your cacti depends on the temperature of the room, the size of the pot and the size of the cactus. Typically watering once every 2 weeks is often the recommended for cacti in Winter, but always feel the soil at the base of the pot through the drainage holes in the base to check whether the soil is dry before watering.
- Move the cacti to an area of more light. The more light the better during Winter so find the brightest room of your house for your cactus to help save it.
- Keep the temperature in the preferred range of 55°F to 85°F (13°C to 29°C) and avoid temperatures lower then 40°F. Most houseplant cacti are native to hot and dry areas so keep it in a room with the preferred temperature range. This helps to ensure the soil does not remain damp for too long after a bout of watering.
The steps of how to save a yellowing cactus in Winter are otherwise the same steps set out above for saving an overwatered cactus that is yellow and mushy.
This means replacing the soil and checking the roots for root rot. Cut back any diseased roots with a sterile pair of pruners and repot the cactus.
I would recommend propagating any offsets, pads or cutting from any healthy remaining growth to help save the cactus as if the root rot it severe the main cactus stem can be difficult to save. Overwatering is the most common cause of a dying cactus.
Cactus Turn Yellow Due to Sun Burn
The reason for a cactus to turn yellow at the top is because of sun burn. Cacti can scorch yellow when they are moved from low light to full sun without anytime to adjust to the increase in light intensity. The sudden increase in light turns the cactus yellow with a scorched appearance.
Most houseplant cactus plants are native to hot and dry conditions and often tolerate full sun.
However they are often cultivated or stored in the store or nursery before sale in an environment with lower levels of light.
Cactus plants are very adaptable and adjust to their environment, even in low light conditions that are less then ideal.
But when they are moved from a shadier location to full sun or even outdoors the cactus is not accustomed to intense blazing sunshine and the sudden contrast in light intensity is the reason the cactus turns yellow.
It is often easy to identify whether sun burn is the reason for your cactus turning yellow (rather then over or under watering) because the side of the cactus that is most exposed the sun has the most scorched yellow appearance.
The sudden increase in light intensity is also associated with an increase of temperature, an increase in the rate the soil dries out after watering and usually a decrease in humidity which can also stress the cactus and contribute the the yellowing.
How to Save a Yellowing Cactus from Sun Burn
A cactus can adjust to full sun after a period of relative shade however, it should be exposed to the higher light intensity gradually by locating the cactus in the sun for 20 minutes longer each day over the course of 2 weeks or so.
This allows the cactus to acclimatize to the increase in light intensity over a period of time, which prevents the cactus from scorching yellow.
If the cactus has been scorched yellow then unfortunately it does not turn green again as the surface of the cactus does not have the capacity to recover from sun burn.
However, whilst the sunburn areas of the cactus do not look aesthetically pleasing, it should not necessarily harm the plant (assuming it has been protected from further sun damage).
The cactus should continue to grow as long as the conditions are favorable (do note that cacti go practically dormant during Winter and do not grow noticeably).
Perhaps the best way of saving a yellow, sun damaged cactus is to propagate the cactus is to propagate it from any offsets that have grown, pads or cuttings of healthy undamaged tissue which allows you to grow more cacti which can grow a healthy green color.
Cactus Turning Yellow and Wrinkled due to Underwatering
Cacti turn yellow because they are not watered often enough or watered too lightly. Cacti require a -soak and dry- cycle of watering to ensure the water has reached the cactus’s roots. If the cactus is watered too lightly the cactus can wrinkle and turn yellow due to drought stress.
A common mistake when caring for cacti is to misinterpret the advice that ‘cacti do not need much water‘ to mean that a cactus only requires a small trickle of water when watering.
If the cacti is watered too lightly, only the top inch or so of the soil becomes moist and the water does not reach the roots where it is required.
Cacti store water in their fleshy stem. If there is not enough moisture in the soil available, the cactus draws upon the moisture reserves in the stem. As the cactus depletes its moisture reserves, the cactus shrinks in size cause the cactus to turn yellow with a wrinkled appearance.
The cactus also turns yellow with a wrinkled appearance if it is not watered often enough. Factors such as high temperatures, more sun in Summer and low humidity can also contribute to a yellow, drought stressed cactus.
How to Save an Yellow, Wrinkled Cactus due to Underwatering
- Water the cactus with a generous soak, so that excess water trickles from the base. This ensures that the soil is evenly moist and the water has reached the roots where it is required. Ensure that any saucers or trays underneath the pot are emptied of excess water regularly to avoid root rot.
- Water the cactus when the soil feels dry at the base of the pot. Typically this means watering your cactus every 2 weeks, but can depend on your climate, the temperature of the room and the potting medium. Always feel the soil through the drainage hole in the base of the pot to determine whether the soil is dry before watering. This is important to void overwatering your cactus.
- Keep the cactus in a room that is between 55°F to 85°F (13°C to 29°C). This is the preferred temperature range of most cacti. If the cactus is turning yellow and wrinkled it can be because the cacti is too close to a source of indoor heat which dries out the soil too quickly.
Cactus that has turned yellow and wrinkled due to underwatering typically recover very well after 2 or 3 watering cycles. A through watering gives the cactus the opportunity to draw up moisture to replace its depleted reserves in the stem which should restore the cactus appearance.
It is important to note that a cactus can recover from a yellowing appearance due to underwatering much easier then from overwatering so always check that the soil is dry before watering.
Will a Yellow Cactus Turn Green Again?
If the reason for the cactus turning yellow is root rot, the soft yellow parts of the cactus do not turn green again and should be cut out of the cacti to prevent the rot from spreading throughout the cactus.
If the cactus has been scorched yellow by sun burn, the cactus does not turn green again. Protect the cactus from full sun and propagate any offshoots, pads or cuttings that remain undamaged to grow a new green cactus.
If the cactus is turning yellow and wrinkled from underwatering then the cactus should turn green again. Water the cactus generously, so that the soil is evenly moist. This helps to roots replenish the cacti’s moisture reserves to restore the cactus yellow appearance back to green and healthy.
(Read my article, how to revive a dying cactus).
- Cacti turn yellow at the base because of root rot due to overwatering. Cacti are drought resistant plants, that require the soil to dry out between each watering. If the soil is consistently damp and the temperature is lower then 40°F the cactus develops root rot which turns the cactus yellow, soft and mushy.
- Cactus turn yellow in Winter because of root rot. Cacti are dormant in Winter and need watering less frequently. Damp, cold soil due to overwatering during Winter promotes the conditions for root rot which causes the cactus to turn yellow and mushy.
- Cacti can turn yellow at the top due to sunburn if they are moved from a relatively shady area to full sun without time to acclimatize to the higher level of light intensity. The sudden contrast in light conditions can scorch the cacti yellow.
- Cactus plants can turn yellow and wrinkled if they are not watered often enough or watered too lightly. Cacti store water in their stem. If it its not watered often, the cactus depletes its moisture reserves causing the cactus to turn yellow and wrinkled in appearance.