Fairy Castle Cactus: How To Care For Acanthocereus Tetragonus

Having recently gone through a name change (this plant was once called Cereus Tetragonus), Fairy Castle Cactus is still a popular houseplant for those who love desert plants. Its slow growth and compact size make it ideal to use in a window sill garden, or, it can be allowed to grow to its full height of six feet and used as a decorative garden feature.

How to Identify Fairy Castle Cactus

Cacti Cactus Fairy Castle

When you are trying to find this type of cactus, look for a cactus that grows tall, thin, and circular trunks. These trunks often grow in clusters. The trunks feature small spines running lengthwise from the top of the trunk down its side and to its base.

How to Grow Fairy Castle Cactus from Seed

This method for propagating a Fairy Castle Cactus is not the most common simply because it takes a long time to see any significant plant growth. If, however, you are determined to grow one of these cacti via seeds, follow these steps:

  1. Harvest seeds from the fruit of a Fairy Castle Cactus
  2. Clean the seeds
  3. Allow the seeds to dry out
  4. Fill a plant container with a Succulent and Cactus Soil Mix
  5. Plant the seeds in the mix after they have dried
  6. Moisten the soil
  7. Keep the soil moist but not soggy and do not water the soil when it still feels wet
  8. Keep the plant container in a warm and sunny place

How to Propagate Fairy Castle Cactus

Fairy Castle Cactus

If you feel that growing one of these cacti from seeds is too time-consuming for you, don’t fear, there are other methods for propagating these plants. The best method is to propagate via cuttings.

Not only does this allow you to make new plants, but it will also allow you to keep the growth and look of your cactus under control. If you’re interested in using this method, follow these steps:

  1. Put on garden gloves to protect your hands from the small spikes on the cactus
  2. Clean a pair of scissors or another type of cutting utensil
  3. Cut off a healthy branch from a healthy plant
  4. Set the branch out for a few days to allow it to callus
  5. Fill a plant container with well-draining soil
  6. Dip the end of the branch in a rooting hormone
  7. Stich the branch into the soil
  8. Set the plant container in an area that is warm but not sunny
  9. Water the new plant a few days after it has been planted and water it only when its soil is dry
  10. Slowly acclimate the new plant to full sunlight

Fairy Castle Cactus Growing Conditions

This plant is ideal for anyone to grow in any part of the world as long as you know its key care requirements. Fairy Castle Cactus may be a hardy plant, but it does not tolerate cold and frost very well, so if you live in that sort of climate, you need to be prepared to grow this plant indoors.

To help you grow it inside, you can purchase and use grow lights and plant heat mats . These two items will supplement the sunlight and the heat that cacti require.

Check the USDA Plant Hardiness Zone Map to find out which zone you live in and confirm whether or not you can plant this cactus in the ground or if you will need to bring it in during cold weather. It is very limited on where it can be planted (zones 10 and 11).

How to Plant Fairy Castle Cactus

Fairy Castle Cactus

While these are slow-growing plants, they will eventually outgrow the plant container they currently call home. When this happens, you will need to remove the plant from its container and replant it in a new and bigger container.

Here are a few tips for working through this process:

  • always wear gloves
  • Plan to repot your cactus during spring or summer to reduce shock
  • Dust off the soil on the plant’s roots
  • Inspect the plant for pests and remove them if necessary
  • Prune the plant’s roots
  • Do not water the plant right after it has been replanted but wait at least a week

Fairy Castle Cactus Potting & Soil

It is very important that cacti be set in soil that will drain off excess water. In combination with this, the plant container it is set in should also drain well. This is because cacti are highly susceptible to root rot from soggy soil.

Try these recommended products for your Fairy Castle Cactus:

Fairy Castle Cactus Water Requirements

As is the case with other types of desert plants, Fairy Castle Cactus should be watered very carefully. If you are uncertain about how and when to water a cactus or just want something to keep you on track with your watering regimen, consider getting a plant watering app .

To ensure that your Fairy Castle Cactus is properly and carefully watered, follow these guidelines:

  • Only water the cactus if its soil is 50% dry from the top down (test it with your finger or a soil moisture meter )
  • Do not spill water on the cactus since this can cause water damage
  • Water the cactus in the soak and dry method

Fairy Castle Cactus Light Requirements

As a desert plant, it is assumed that Fairy Castle Cactus requires a lot of direct sunlight; however, this is not entirely true. This type of cactus can actually get sunburn if it is exposed to large amounts of direct sunlight for long periods of time.

To prevent sunburn and still give the plant adequate sunlight, set it in a place that gets six hours of morning sunlight. If this is not possible, set it in a place that gets filtered but bright sunlight.

If adequate sunlight is not available to you, especially in winter or extreme northern and southern climates, try setting your Fairy Castle Cactus under some grow lights.

Best Fairy Castle Cactus Fertilizer

cure farms

Newly planted cacti do not need to be fertilized since their new soil should have plenty of nutrients in it.

When it does come time to fertilize your Fairy Castle Cactus, you will want a fertilizer that is specifically designed for cacti and something that can be diluted. Also, the plant will only need to be fertilized during spring and summer.

Try Cute Farms Succulent Cacti & Aloe Fertilizer for all your desert-loving plants.

Best Fairy Castle Cactus Companion Plantings

If you intend to grow a cactus, why not gather a few more plants to set alongside it? There are so many other easygoing plants that will make your gardening routine a breeze. It will also be very rewarding to see so many beautiful plants growing together in harmony.

Here are a few choice plants that will work wonderfully next to your Fairy Castle Cactus:

Callisia Repens

Callisia Repens

This native of the tropical regions of South and Central America is actually semi-succulent. It grows vining stems covered with soft and tiny leaves shaded in purple and green.

This color scheme will provide an excellent contrast to the solid green branches and harsh spikes of a Fairy Castle Cactus.


  • Callisia Repens is very easy to care for
  • Callisia Repens is easy to propagate
  • Callisia Repens has care requirements that are similar to those of Fairy Castle Cactus
  • Callisia Repens is not toxic


  • Callisia Repens is susceptible to infestations of aphids and mealybugs



If ever there was an easygoing plant, this is it. Not only are aloe plants unfussy, but they are also graceful and beneficial to one’s health.


  • Aloe is very easy to grow and care for
  • Aloe is easy to propagate
  • Aloe has care requirements that are similar to those of Fairy Castle Cactus


  • Aloe is mildly toxic
  • Aloe is susceptible to infestations of aloe mites

Rat Tail Cactus

Rat Tail Cactus

This plant will be a wonderful addition to your cactus and succulent garden since it grows in a vining pattern that makes it ideal for a set in a hanging planter.


  • Rat Tail Cactus is very easy to grow and care for
  • Rat Tail Cactus has care requirements that are similar to those of Fairy Castle Cactus


  • Rat Tail Cactus is covered in sharp spines

Fairy Castle Cactus Diseases and Common Problems

Most plants face infestations and infections as part of life and Fairy Castle Cactus is no different. Fortunately, most plant diseases and pests can be prevented or treated easily. Take some time to learn what the common issues are that these plants face and how to identify them. This is a great way to care for your plants.

Here are a few of the most common issues faced by Fairy Castle Cactus:


Evidence of an infestation of mealybugs is small white spots that look like cotton on leaves and stems. To deal with an infestation of mealybugs, follow these steps:

  1. Spray a solution of alcohol and water on the leaves
  2. Remove and kill any bugs that you find
  3. Spray the plant neem oil or insecticidal soap every few days

Root Rot

Evidence of this problem is when a plant turns brown, yellow, and mushy. To treat this problem, let the soil dry out completely and set the plant in a place where it will get plenty of airflow. If it is still struggling with too much water in its container, follow these steps:

  1. Remove the plant from its container
  2. Wash off all the dirt from its roots
  3. Cut off any roots that are rotten
  4. Replant the plant in a clean container with fresh soil
  5. Wait to water it for a few days

Fairy Castle Cactus Treatments and Maintenance

DiatomaceousEarth Food

Prevention is the best method for treating and maintaining healthy plants. Here are a few tips to help keep any of your plants healthy and disease-free:

  • Check it for signs of disease and infestations regularly, and treat them quickly.
  • Clean the plant regularly with neem oil.
  • Learn how to properly water and feed your plant.
  • Make sure your plant is set in an area with adequate amounts of sunlight, heat, and humidity.
  • Mix diatomaceous earth into the soil of potted plants.

Where to Buy Fairy Castle Cactus Seeds Online

It may be a little difficult to search for seeds for this type of cactus online, but the following three shops are a great place to start:

Where to Buy Mature Fairy Castle Cactus Online

These cacti are easy to find in stores and online. If you’re ready to grow a garden full, then check out these great online shops:


Question: Is Fairy Castle Cactus Toxic?

Answer: No, it is not considered toxic. But by just looking at the plant, it is still recommended that you keep pets and small children away from its prickly spines.

Question: Does Fairy Castle Cactus Produce Blooms?

Answer: Yes, it can produce blooms, but it is rare to see this happen when it is kept indoors. The blooms that are typically set on these cacti in stores are fake and can be removed or left to fall off on their own.

Question: Does Fairy Castle Cactus go Through Cactus Corking?

Answer: Yes, you may notice as your cactus ages that it is turning an unsightly brown color. Rather than being a deadly fungal disease, this is a natural process known as cactus corking.

It should begin at the base of your cactus and slowly move upward in an even pattern. The corking should not be soft or squishy; it should be firm.

If your plant is turning brown but is not firm or evenly discolored, you may need to examine it for root rot instead.


Question: For how long does a Begonia Boliviensis live?

Answer: Begonia Boliviensis can live for about two to three years with adequate care and maintenance.

Question: How often do Begonia Boliviensis plants bloom?

Answer: Begonia Boliviensis plants bloom from spring to fall.

Question: Are Begonia Boliviensis plants toxic?

Answer: The plant tends to be toxic to animals. As such, it is crucial to keep Begonia Boliviensis away from infants and pets.

In Conclusion

Fairy Castle Cactus is a quaint little desert plant that with time and good care can become a large and lovely plant. If you want to grow something that is fun and easygoing and something that will allow you to share it with others, then look no further than this cactus variety.

Research Citations

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top