Cacti are described as one of the most "easily recognizable, and morphologically distinct families of plants." They are prized in the landscape and as houseplants for their unique appearance and relatively low water and maintenance requirements. It is cause for alarm when a slow-growing cactus appears to suffer or die. The death of a cactus is most likely caused by or associated with excessive moisture around the roots, although factors like a too-deep planting, low temperatures, and fungal pathogens also potentially present problems for a cactus.
Poorly-drained soil, particularly when combined with overwatering, can quickly kill a cactus or leave it vulnerable to invasion by soil-borne fungal pathogens. Cacti require fast-draining soil, but soil with too high a sand content does not retain sufficient moisture and nutrients. A potting soil labeled for use with succulents or sand amended with well-rotted compost is appropriate. In outdoor plantings, amending the soil, so it contains up to 25% pumice improves soil drainage. As a general rule, cacti require only when the soil 2 to 3 inches (5 to 7.5 cm) below the soil surface is completely dry, or about every two weeks when the cactus is growing in good, well-drained soil.
Planting a cactus too deeply can lead to its death. Positioning a cactus at the same soil depth it was grown at in the nursery, or a previous container is crucial. However, it is perhaps tempting, especially with columnar cacti, to bury enough of the stem to hold it securely in place or match the heights of multiple cacti. All green stem tissue should remain above the soil. When a newly-planted cactus starts to lean, a brace made from wood, no additional soil or medium packed firmly around the base of the plant, is the best way to hold it in place until it supports itself.
Various fungal rots or wilts, including Armillaria root rot, Fusarium, and Phytophthora, are potentially problematic on cacti. Cacti affected by these diseases may suffer from slow growth, decline, visible rot or discoloration, and even death. Cutting into infected, cacti reveals discolored tissue. Problems with these pathogens are avoided by preparing the site well, so it offers good drainage, avoiding overwatering and promptly removing plants that show symptoms of rot before it spreads. Where fungal wilts have been a problem, soil solarization kills many pathogens and pests in the soil.
Freeze damage or sunburn, generally only cause cosmetic injury on a cactus, but this type of injury could appear as black or yellow dead areas on the plant. Freeze injury appears first as a blackening of the areas of the plant that were exposed to the cold before these areas become dry, crisp, and sometimes yellowish. When the freeze is not very hard, the cactus usually outgrows the damage within a few years. Keeping indoor cacti away from cold drafts or windows during cold weather and covering cacti in the landscape with a cotton sheet on nights when temperatures dip near freezing offers adequate cold protection.
Sunburn of cacti most commonly occurs when a cactus grown in a greenhouse or kept indoors is introduced to an area with full sunlight without a period of acclimation. Cacti that are sunburned turn yellow, and the epidermis dies, causing a permanent scar, but the cacti generally recover. Sunburn is avoided by planting cacti in the same direction they were previously oriented or gradually introducing a cactus to the amount of sun in its new environment.
Subscribe now and be up to date with our latest news and updates.
When a cactus begins dying, it comes down to basic care. Cacti are such resilient plants that it’s practically impossible to kill them unless you’re merely caring for them too much. Overwatering is one of the most common mistakes new gardeners make with these desert plants, as root rot is an actual reality with these species. Take care to provide your cactus with adequate sunlight, water only when necessary, and keep it out of direct cold elements.
Some species require more care than others. If you find yourself unable to care for your cactus correctly, consider purchasing one of the previously mentioned species. Cacti like Saguaro Cactus don’t require much upkeep and can live in an arid environment for decades.
Now that you’ve found out the possible culprits behind your dying cactus, it’s time to take a look at how to care for your plant to keep it looking its best.
Cacti are incredibly hardy plants and will store water in their cells to prepare for drought or their dormant season (the winter). In most areas throughout the United States, rainfall is enough to keep an outdoor cactus adequately moist and healthy.
However, if you’re experiencing a particularly rough drought or your cactus is indoors, it’s recommended that you water your cactus once a month. If the soil still looks moist when the next watering cycle comes around, wait another week before watering.
Watering in the winter is something that shouldn’t be done unless you’re in an area where winters don’t drop below the mid-60s degrees Fahrenheit. If your winters are practically none, you should still water your cactus less than you would during the warmer months — only about once or twice during the winter, depending on the temperatures.
Though there are a few jungle varieties of cacti, in general, cacti are desert plants. Rather than receiving their water from spritzes of humidity or constant rainfall, a cactus’s roots deeply penetrate the soil to reach the remaining water from the last rainfall and stores as much as possible until the next rain shower.
Because cacti aren’t native to areas with high humidity, watering your cactus with a fine mist or by pouring water directly on its stem will dull the appearance of your cacti, and eventually, lead to surface rot. Instead, you should either apply water directly to the soil (taking care not to water the base of the plant directly) or set your potted cactus in a saucer of water so that its roots can reach and water themselves. Be sure to take the cactus out of the saucer once the soil is dampened.
When watering the soil directly, you should use a slow-moving stream, such as a garden hose turned on low, and water deep enough so that it begins draining from the pot.
Though the amount, and type, of sunlight a cactus needs varies from species to species, most cacti will need about 4 to 6 hours of sunlight per day. Remember to check the light requirements for your particular plant, as some species will need full sun, part sun, or minimal sun each day.
If your cactus isn’t receiving the proper amount of sunlight, it will begin to display signs of weakness and discolorations such as:
On the other hand, a cactus that receives adequate light will:
Placing your indoor cactus in a south-facing window will ensure that it receives enough light during the day. Most cacti will not need direct sunlight and can thrive on indirect light, so just as long as the window is receiving bright, indirect light, your cactus should do well.
As for outdoor cacti, it’s best to plant them in an area that is shielded from intense, direct sunlight at the hottest hours of the day. For example, plant your cactus in an area that is shaded around noon, but receives around 6 hours of sunlight in the afternoon and evening.
If you place your cactus in an area that receives too much sun, especially the direct sun, you risk sunburn damage to your plant. Sunburn in cactus manifests itself in brown or yellow spots on the pads of the cactus and will also lead to a dried appearance if the problem isn’t remedied.
An excellent way to combat the effects of sunburn is simply by moving your cactus to another area or by planting taller, thicker plants, such as desert shrubs, next to the cactus to block any harsh sunlight. You’ll want to act swiftly, though, because sunburn in cacti happens rapidly and will end in an unfortunate demise for your plant if nothing is done.
Because cacti were created to retain water for extended periods, they also suck any moisture up quickly and won’t need to have wet soil to stay healthy. In fact, moist soil will actually cause root rot in cacti, so it’s essential to plant your cactus in a soil that drains well to avoid any health issues.
Sandy or gravelly soil is best and is especially useful for seasons where rain is frequent or abundant. This is because well-drained soil allows any excess moisture that may be provided to your cactus to move away from the roots, protecting them from pooling and rot. You can either find a premade cactus soil online or at your local plant nursery or substitute ⅓ of your regular potting soil with sand to create the ideal soil for cacti.
Our favorite cactus potting mix is the Hoffman 10404 Organic Cactus and Succulent Soil Mix. It’s formulated with both jungle cacti (like Christmas Cactus) and desert cacti in mind, providing the proper drainage to allow your cactus to get adequate water without puddling excess moisture at the roots.
It’s also organic, meaning that it’s a healthier formula not only for your cacti but also for the earth and your family. Lastly, it contains an abundance of nutrients to encourage growth, vibrant colors, and brilliant floral blooms in the spring and summer.
What We Like:
There is a time and place for everything, and that includes fertilizing your cactus. Cacti should be fertilized, but infrequently (only once every 2 to 4 weeks), and only in the spring when the plant is growing and preparing for the upcoming months of dormancy.
Fertilizing your cactus in the spring will help it to store essential nutrients to sustain itself whenever nutrients are scarce in the winter. You don’t want to fertilize your cactus during the harsher months of summer and winter because your plant’s primary focus during those times is to stay alive rather than grow.
Of course, you should always opt for a fertilizer that is formulated especially for succulents and cacti. We suggest the Miracle-Gro Succulent Plant Food for indoor cacti. It’s very affordable for all gardeners (even the budget-conscious) and works well to provide instant nutrients to your plants.
This fertilizer is a liquid and comes in an easy-to-use pump bottle. You can apply it directly to the soil or mix it with water the next time you water your cactus to give it an additional boost. It’s recommended that you use this fertilizer once every two weeks for cacti that have been relocated to a new area of your yard, repotted, or brought indoors after being purchased.
Once your cactus plant is established in its new home, you can lengthen the amount of time between fertilizing to 4 weeks or a month. Take special care not to apply this fertilizer directly to the cactus, as it will cause chemical burns on the pads.
What We Like:
Overall, the Miracle-Gro formula for cacti is an excellent option for potted cacti or outdoor cacti that aren’t receiving the nutrients they need from the soil.
No matter how well you care for your cactus during the spring and summer, when winter strikes, it can be a death sentence for many cacti species. Though there are cacti that can withstand temperatures sometimes as low as -30 degrees Fahrenheit, the majority of cactus species on the market for home gardening can only survive down to freezing — and for very short periods.
It’s essential to take the necessary precautions before winter rolls around to prevent frostbite or potential withering of your cactus. Care (watering, light, and temperature) for your cactus also changes slightly from care during the rest of the year.
In the next few sections, you will learn how to care for your indoor and outdoor cacti in the winter.
Winter is the dormant season for cacti, meaning their processes naturally slow to keep them from expending energy and nutrients during the harsh season. Indoor cacti have the advantage of not being directly exposed to outdoor elements. However, with the decrease in light and increase in the frigid temperatures, there is some improvising involved in its care.
Because your outdoor cactus is in direct contact with the icy elements, there will be a bit more work to do on your part to keep it from too much exposure. Frigid winds can lead to frostbite in exposed cacti, and too much snow can lead to both surface and root rot once it begins to melt.
Is your cactus plant changing color? Does it look unhealthy or unhappy? If so, then you should be worried because you might be staring at a dying plant. The truth is that cacti plants are hardy and will thrive with minimal care. However, just like any other living thing, they have weaknesses, and if you are not careful or don’t take action swiftly, the plant can develop diseases, which will eventually lead to death.
So, how do I know if my cactus is dying? Well, one of the easiest ways to know if you are staring at a dying cactus is checking the plant’s overall condition. Typically, a dying cactus feels shakier in its potting mix and may appear as though it wants to fall off. This is a clear sign of root rot and other underlying problems. Some plants may also change color, develop soft segments on the stem, or start producing a foul smell.
Read on to find out some of the telltale signs of a dying cactus and some of the common reasons why cactus plants die. We are here to help you grow healthy and happy plants.