Plant Care  |  November 12, 2020

Cereus Cactus Care


PRO TIP: Withhold water from the plant for about four weeks in January or February to encourage new growth in the warmer seasons.

Native to South America, the Cereus Cactus (Cereus peruvianas) is a striking plant. It has a blueish-green hue, distinct spiny ribs, and can grow up to incredible, tree-like heights in the wild.

The Cereus Cactus appreciates a warm, dry environment with minimal water, and plenty of light. This desert beauty will thrive in high light conditions, so placing it in a window where it will receive direct sunlight is ideal — preferably a southern or western facing window, as they are typically the brightest. This plant will not tolerate low light conditions.

If you are unsure about lighting conditions in your home or office, we have a guide for how to measure light in your space.


Cereus Cactus Close Up

The name for this cactus is derived from Greek and Latin words meaning “wax” and “torch”.

Routine Maintenance

PRO TIP: If in doubt, let it drought! The biggest killers of these plants is root rot caused by overwatering. In New York, cacti rarely receive enough light to require watering more than once or twice a month.

Always be sure to assess your plant’s watering needs upon receiving it. Before giving your plant a drink, it is best to check the moisture level in the soil first to ensure it isn’t moist right beneath the surface. Also, consider aerating the soil of your plant before the initial watering. We compact the soil to avoid shifting during transit, so aerating can help the soil breathe and allow moisture to be released.

Cereus Cacti like to dry out completely between waterings. The most common mistake made with these plants is overwatering. Make sure that you are letting the soil thoroughly dry before giving your plant water. Cereus Cacti are susceptible to root rot, so it’s very important that you do not water the plant if you detect any moisture in the soil. During the winter months, watering frequency should decrease, sometimes to as little as once a month.

Rotate your plant periodically to ensure even growth on all sides and dust the stalks often so the plant can photosynthesize efficiently. When dusting the stalks, also take the opportunity to inspect them and keep an eye out for pests. Cereus Cacti are susceptible to scale, an indoor houseplant pest that appear in the form of small brown scabs. It is very easy to treat, however it’s best to inspect your plant regularly to ensure you catch it in the early stages.

Remember each plant is a unique living thing and may have varying needs, especially in their individual locations. Pay attention to the condition of your Cereus Cactus and its watering needs and you will have a long and happy relationship.

Frequently Asked Questions

Is it possible to under water my Cactus?

  • It is rare, but yes. Signs of under watering are typically brown edging or markings. The cactus stalks would be dry and brittle, as opposed to mushy and soft. When watering an underwatered cactus, remain conservative with the amount given because overwatering is still a possibility.

How can I tell if my Cactus is getting too much water?

  • Generally, a cactus will become less stable, droopy, and brown at the base if it is receiving too much water.

How do I know if my Cactus has scale?

  • Scale is a small, flat, round pest that attaches itself to the flesh of the plant and remains stationary. If you see small raised bumps on your cactus that are easily removed with a paper towel or q- tip, it is likely scale. Good news is it is very easy to remove the pest and treat the plant! Begin by scraping all the bumps off, and treat the plant by with a mixture of insecticidal soap, or neem oil, and water. Follow the instructions for dilution on the bottle. Dip either a soft bristled toothbrush, a q-tip, or a paper towel in the mixture apply to the treated areas. Spray the mixture lightly on the plant and soil and let it rest. Repeat in seven day intervals until you no longer see the scale. Be sure to treat the plant in the evening as the insecticidal mixture can burn the plant's flesh in direct sun.

How often should I fertilize my plant?

  • In general, houseplants will thrive when they are fertilized spring through fall. Fertilize once a month with an organic houseplant fertilizer, following the package instructions for dilution and administration. Greenery NYC uses an organic potting mix with a slow release fertilizer in the soil, so your plant will not need fertilizer within the first 6 months of receiving it.

How often does my plant need to be repotted?

  • We suggest repotting every 2 - 3 years. Cacti are slow growing, and they prefer to be somewhat pot bound so you can wait longer than you would with most houseplants. Be sure to choose a potting vessel 2”- 4” larger in diameter to allow for growth. Don’t choose a pot much larger than this as this could drown the plant's roots. If you prefer to maintain the current size of your plant, repot into the same vessel, providing new soil and trimming away some roots and foliage. Spring or summer is the ideal time for repotting as the plant is at its strongest. When repotting a cactus, be sure not to water it for at least a week after disturbing its roots, as they can enter a state of shock during the process which can make them more prone to overwatering. They return to normal after several days.

Standard Planter Instructions

All of our Standard Planters include a removable drainage plug to give our customers the option of drainage. While no drainage is sometimes preferred for its aesthetic simplicity, we don't recommend this option for beginners as watering mistakes can be hard to rectify.

Whether you choose to use drainage or not, we always recommend using a layer of drainage (such as our Aeration Stones) at the base of the planter. A drainage layer allows the plant's roots access to oxygen in the pockets between the drainage medium, and a lack of drainage can cause anaerobic damage to your plant.

If you decide to utilize the drainage hole for your pot, make sure to include a Plant Saucer beneath your pot to collect excess water. For most plants in standard planters, we recommend watering about once a week. Water the soil mass until water begins pooling in your Plant Saucer.

With no drainage hole, you will need to be more precise in your watering. While we would love to give you a specific measurement of water to provide for your plant, the reality is that a plant's water requirements vary wildly depending on factors such as light exposure and the overall health of the plant. You will need to learn to tell when the plant is thirsty based on how its foliage looks. Droopy foliage is usually the first sign: when your plant looks a little slumped over that's usually a visual indicator that it's thirsty.

The best solution for checking your plant's moisture level, drainage hole of not, is to use a Soil Probe to determine the moisture content of the soil at the bottom of the planter.

Self Watering Planter Instructions

The Self-Watering Planters require a deep and thorough watering of the topsoil after they are first planted. This is important because the roots of the plants first need to grow into the reservoir in order to drink from it. Water your plant from the top for two to four weeks before using the reservoir. During the dormant seasons, or for plants that have slower growing habits, consider top watering for longer.

TEST: After the initial top water period, fill the bottom water reservoir. If the water in the reservoir is absorbed into the planter, it means the plant is ready for regular reservoir servicing. If not, be sure to continue top watering for a few more weeks until the plant has started drinking from the reservoir.

RESERVOIR SERVICING: Once the reservoir empties on its own, do not refill the reservoir right away. Similar to how humans need a breath of air between gulps of water, most plants require a drying out period. Allow for the reservoir to empty all the way between watering. All plants are different in their needs so the amount of time the reservoir sits empty will need to be determined, but know that for most plants this period is between 1-3 days. 

From here on out, you should rarely topwater the plant while using the reservoir system. Watering from below allows the plant to drink at its own pace, and can help combat certain issues like fungus gnats by allowing the top layer of soil to dry out more. Please note that if your plant's soil dries out too much, it can impair the wicking ability of the Aeration Stones in your planter. If your soil becomes too dry, we recommend giving it a thorough watering.

For more information on our Self Watering Planters include planting instructions, visit our blog post on How to Use Our Self-Watering Pots.

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