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Moon Cactus | How to Grow & Care Guide

The moon cactus is a highly popular choice amongst succulent and cactus plants. You may assume it’s easy to take care of plants, and especially when it comes to a cactus.

There is a huge misconception that in order to take care of a cactus, you only have to worry about watering it a minimal amount each year. Truthfully, all plants require specialized care depending on their unique characteristics. 

There are a variety of cactus types and each one needs curated care in order for them to thrive and grow. If you are wanting to get your own moon cactus, follow this moon cactus plant care and growth guide.


Moon Cactus Plant Details

Moon cactus, or Gymnocalycium mihanovichii are one of the most notorious cactus specimens

Moon cactus, or Gymnocalycium mihanovichii are one of the most notorious cactus specimens. They are commonly found in locations such as Brazil, Bolivia, Argentina and other South American deserts. 

The moon cactus is identified by its vibrant flower on top of the cactus stem. The flowers are bubble shaped and have small spikes bunched together in clumps.

A moon cactus flower can come in pink, orange, yellow and sometimes red. These beautiful plants are actually a product of human design. The cactus stem is known as a rootstock cactus, and the flower itself is of the Hibotan breed.

Through plant grafting processes, the Hibotan flower and rootstock cactus that make up a moon flower were combined. The flower is able to survive on the cactus stem after being grafted to that portion of the plant. 

The reason as to why the flowers maintain their vibrant hue is because there is no chlorophyll in the bulb itself. Though these plants have a complex upbringing, they are easy to care for, making great beginner and house friendly plant options.

How to Grow Moon Cactus

How to Grow Moon Cactus

As previously mentioned, moon cactus plants are a product of grafting. Unless you want to attempt the tricky process of grafting a moon cactus from the start, there are other ways you can grow this plant yourself.

Sometimes, moon cacti are sold right after they have been grafted. Choosing this route will give you more responsibility, but is still an achievable way to grow moon cactus plants.

The two halves of the plant (the cactus stem and flower bulb) are packaged together. The plant halves will then start to heal together, and the grafting process will be finalized shortly after potting. This route is the fastest method and is successful as long as you correctly care for the plant. 

“The other option when it comes to growing a moon cactus is via seed packets. This method is time consuming, and the plant itself takes up to a year to reach its full form. When planting moon cacti seeds, you need to complete the germination process,” warns Charlie Morton, writer at State Of Writing.

This includes sowing seeds over a succulent mixture, and proceeding to cover them with fine grit. You’ll need to keep the soil moist, but do not drench the seed and soil mixture in water. Keep the soil in a warm and dry location so the germination process can go smoothly. 

Overtime, the seeds will form into small versions of the moon cactus plants. This is when it’s time to replant them in a bigger space, preferably grouped together for the best result.

Buying Gymnocalycium Mihanovichii

Growing a moon cactus during the early stages may not be ideal for all plant owners. You can always buy ready to pot moon cactus plants from your local florist shop.

From there you can continue to grow the plant at a more feasible stage. You can also learn to propagate moon cactus plants by using full grown specimens to graft.

Pieces of rootstock cactus can be reused and grafted to a Hibotan flower to produce new copies.

How to Propagate Moon Cactus

How to Propagate Moon Cactus

Though it’s challenging to propagate your own moon cactus plants, it can be done with the right mindset. If you are a garden novice, botanist, or up for a challenge, grafting a moon cactus plant can be a positive experience.

You can learn to graft your own moon cacti in the comfort of your own home. 

1. Preparing the Plants

Using a sterilized knife, cut the scion of the rootstock cactus. If you cut the rootstock correctly, you’ll be able to see a circle shaped tissue. 

2. Grafting the Plants

After you prepare the rootstock, you can attach the Hibotan flower bulb to the vascular tissue. To keep the plants mended together, plastic bands can be used to hold the two sections in place.

3. The Fusion Process

When you’ve successfully grafted the plants, you can remove the bands. You can then carefully plant the specimen in soil with drainage. 

When the rootstock and Hibotan flower are fully fused together, then you’ve successfully grafted a moon cactus plant. You can even propagate your moon cacti if offsets of the plant are grown by attaching them to another piece of rootstock.

Caring for Moon Cactus

Caring for Moon Cactus

Now that you are aware of the options when it comes to growing, and planting your own moon cactus plants, here is how to take care of them.

These beautiful plants don’t need too much attention, but it’s still crucial that you know how to take care of them. These are the specific requirements of moon cactus plant care.

The first step of caring for moon cactus plants is placing them in a healthy, suitable, and beneficial environment. Plants need to be kept in the correct climate or they can’t survive. 

This is why caring for your moon cactus plants can be tricky if you are in a cold environment with minimal sunlight. 

Moon Cactus Sun Requirements

Moon cacti need only a small amount of sunlight for the most part. On bright days, make sure to place them in the shade, or use blinds to counteract the rays.

In the wild, they thrive because they are protected by fellow cacti that have grown taller than the rest. This is why it’s important to plant multiple moon cacti in groups so they can shade each other.

During cooler days, they can benefit from more sunlight to make up for lower temperatures. Really, they need a healthy mix between shade and sunlight to survive.

While the flower itself doesn't go through photosynthesis, the rootstock does. This means if the rootstock doesn’t get enough sunlight, the plant won’t receive enough essential nutrients.

If possible, avoid having the flower receive direct sunlight, and make sure the rays are directed primarily at the rootstock. While it’s hard to balance the sunlight levels while caring for your moon cacti, it can be achieved with both effort and attention. 

Best Soil for Moon Cactus

When getting soil to pot, plant and grow moon cactus, focus on finding soil that supports the rootstock. Since the flower isn’t in the soil, and doesn’t photosynthesize, it doesn’t get impacted by this requirement.

The rootstock performs best in rich organic soil, with a low pH balance, and high draining rate. Repotting your moon cacti is a helpful process, and it’s best to do this during the summer.

You can trim off any dead parts of the plant, move it into a bigger pot if necessary, and ensure there isn’t any extra soil in the pot itself. 

Moon Cactus Humidity Needs

A common mistake amateurs make when caring for moon cacti is placing them in overly humid locations. This causes cacti to slowly die, and grow weak.

Cactus plants are typically found in the deserts; cacti thrive in warm and dry climates. If you live in a humid climate, you’ll need to rely on ventilation. Air conditioning, opening windows for fresh air, and using dehumidifiers can all help you create a perfect low humidity level for your cacti.

As for temperature levels, they need to be stored in locations with no lower than 60 degrees Fahrenheit. If heat is an issue, you can always get a plant light to increase the warmth your moon cactus plants are receiving.

If you live in a part of the world that experiences winter, snow and frost, keep your plants inside during that time! During summer, you can strategically place your cacti outside, but don’t leave them out once temperature levels begin to dip.

Moon cactus flower can come in pink, orange, yellow and sometimes red

Don’t make the mistake of thinking that a humid climate is beneficial to your cactus plants. While they do thrive in heat, they can’t survive with an overload of moisture.

When you are able to curate the right environment for moon cactus plants, you can focus on fulfilling the other needs of this specimen. This includes care needs like watering, soil maintenance, and use of fertilizer when tending to your moon cacti. 

Watering Moon Cactus

The rootstock of moon cacti are well adapted to drought and low moisture. This means that you rarely have to worry about watering the plant. The only case in which you would have to water your moon cacti more frequently if you lived in a climate with high humidity and warm weather.

In this case, don’t overwater your cacti, and instead wait for the soil to be completely dry. Then add just enough water to remoisten the soil so that it’s slightly damp to the touch.

Even just a small excess of water can hurt your moon cactus plants. This is why planting them in a pot, box, or other container with drainage holes is smart. This will allow excess moisture to escape so your cacti won’t suffer.

You will likely only have to water moon cacti once a week, but during summer months and warmer portions of the year, watering can be increased to 2-3 times a week. 

When to Use Fertilizer

Moon cacti don’t need to be fertilized, but it can boost their growth and overall health. Throughout the growing season, fertilizer can be used once a month to aid in the plant's growth. 

Growing season occurs from April to September. Once it’s winter, there is no point in feeling your moon cacti.

Common Moon Cactus Pest and Problems

The first step of caring for moon cactus plants is placing them in a healthy, suitable, and beneficial environment

All plants are susceptible to bugs, root rot, and other issues. Root rot can occur if you immediately water a repotted cacti. Allow a week for the roots to settle into the fresh soil, and use fungicide on any cuts in the rootstock.

This will help you prevent root rot which will kill your moon cactus plants. As for bugs and other pests, you'll need to isolate the infected plants.

To remove the bugs (often spider mites or mealybugs), you can use alcohol dipped on the end of a q-tip. Moon cacti rarely get bug infestations so it’s not too major of a concern. 

Here is a more details guide on how to deal with mealybugs in your garden.

Can't get enough of cactus plants? See more growing guides below:

Owning Your Own Moon Cactus Plants

These plants are gems amongst the succulent and cactus plant category. They are easy to take care of in most cases, and have minimal downsides.

Moon cacti are also safe for pets and children as long as they are not consumed, and the flower isn’t touched. If you want to get your own moon cactus, use this guide to get your started!

About the Author Mabel Vasquez

Mabel has enjoyed a long career as a horticulturist, working in nurseries and greenhouses for many years. Although she loves all plants, Mabel has developed a particular passion over the years for herb gardens and indoor plants. Mabel has since retired from her horticulture career and loves sharing her many years of experience with our audience here at Sumo Gardener.

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