Moon Cactus – Gymnocalycium Mihanovichii Growth, Care & More

We’ve noticed that looking for the answers to questions about Moon Cacti is a difficult and tedious process. So, we have gathered the most frequently asked questions on Moon Cacti and compiled them in this one helpful list below.


What Is The Moon Cactus?

The Gymnocalycium Mihanovichii is a species of cacti native to South America. The plant’s varied colored mutations are formed from a lack of chlorophyll. This species is then cultivated and hybridized, or grafted, with the hylocereus cactus, make the “Moon Cactus”.

From the lack of chlorophyll, it is sometimes called an albino cactus, despite its multiple varieties that have colored tops and or tips.

moon cactus

What Is The Common Name Of Gymnocalycium Mihanovichii?

The common names for the Gymnocalycium Mihanovichii are “Moon Cactus”, “Ruby Ball”, “Red Cap”, “Red Hibotan” and “Hibotan cacti”.

The most common name “Moon Cactus” comes from its yellow and orange varieties, sometimes including the red variety, resembling the color of the moon.

“Ruby Ball” and “Red Cap” refer to the red colored top of the cactus.

“Red Hibotan” and “Hibotan cacti” refers to its full botanical name Gymnocalycium mihanovicii friedrichii “Rubra” or “Hibotan”, adding on to the red topped cactus.

History Of The Moon Cactus

The species of cactus was first discovered in 1903 by Alberto Vojtěch Frič. It was later first fully descripted by Robert Louis August Maximilian Gürke in 1905 and then placed in the Gymnocalycium genus by Nathaniel Lord Britton and Joseph Nelson Rose in 1922.

Since the cactus can change very often with no fixed patterns, it is commonly grafted with other plants to make hybrids or mutants.

This is a very interesting point about this succulent. Each plant mutates, changes and adapts on its own.

You might think that because you cut off a piece of a Ruby variety that when you allow that to callous over and plant it that you’d get a Ruby growing in that pot. That may or may not be the case.

This plant could change into another variety for all sorts of reasons, many of which scientists are still discovering to this day.

However, we do know a few of the reasons it adapts, and they are: stress, availability of water, time of the year it was planted, available nutrients in the soil and most importantly, the plant that it’s grafted too.

The most common succulent that the cactus is crossbred with is the Hylocereus plant.

Because the plant’s mutant variations have no chlorophyll of their own, an array of different pigments become visible from under the cactus as they are nearly translucent at this stage.

So, since chlorophyll is the main chemical in the energy production called photosynthesis in plants, these mutants die at the seedling stage unless they are crossbred with a plant that has its own chlorophyll such as the Hylocereus.

Moon cactus

What Are The Benefits Of The Moon Cactus?

Moon Cacti are a great starter plant for new gardeners. This cactus requires low maintenance. It has been proven in studies that owning a cactus can increase mental productivity by up to 12% and bring the owner into a state of positive energy.

They also add brighten up the room and add character with their colorful tops and semi translucent appearance.

How To Take Care Of The Moon Cactus?

The best soil for the Moon Cactus is regular cactus mix that can be well-drained.

For better plant nutrition and growth, many people make their own homemade Moon Cactus soil. The recipe calls for equal peat-based potting soil mixed with sand (coarse sand is the most recommended), this homemade mix works better than regular cactus soil mix but only works well if you’re using a pot that also drains very well to avoid standing water.

One of the best pots to use are those with short legs or ridges on the bottom that also have holes in the bottom as well. They are best used on a tray that catches the excess water as it drains. These pots come in most materials with Terra Cotta being one of the most popular.

You can fertilizer your Moon Cactus with a quarter teaspoon of 15-15-15 water soluble fertilizer mixed with 1 quart of water every watering session during its growing period in the spring and summer.

If you only have one plant you can reduce the fertilizer and water using the above measurements as your reduction guide for the correct ratio.

The recommended temperature for the Moon Cactus is 64°F to 77°F (18 – 25°C). This plant does not like direct light. By placing it in some bright shade such as a covered patio, your cactus will thrive happily.

Your Moon Cactus does not need a lot of water since most cacti are drought tolerant. Check your plant’s soil before you decide to water it, if the soil is bone dry, water your cactus.

If you’re looking for more of a timed schedule, you can check the plant every 14 days (2 weeks) to see if the soil is dry enough during its growth period. If it is, then water it, if not then don’t.

During its dormant times of the year check once per month. If it’s bone dry, then water it, if not then hold off and check again in 2 weeks.

In the winter months, your plant will need less water since it goes into its dormant ‘near hibernation’ phase during that time.

What Is The Best Soil For The Moon Cactus?

The best soil for the Moon Cactus is a regular cactus soil mix but it is reported that people who use a homemade soil mix have a better result growing their cactus.

The recipe for the homemade soil mix calls for equal parts peat-based soil and coarse sand. Just blend them together and you’re done, no need to layer them.

However, you can put a thin layer of gravel of pea gravel at the bottom of the pot before adding your soil mix on top of that. This will help ensure proper drainage and help avoid all the problems that standing water can cause with succulents.

watering cactus

What Is The Best Fertilizer For The Moon Cactus?

The best fertilizer for the Moon Cactus is a mix of a quarter teaspoon of 15-15-15 water soluble fertilizer blended with 1 gallon of water. It is suggested to use this fertilizer every two to four weeks in the spring and summer for better growth.

During the fall and winter months you can reduce the watering to once per month maximum and stop using fertilizer all together.

If you have fewer plants and don’t need a gallon of fertilizer water, just use that same ratio when reducing your water and fertilizer.

What Is The Suggested Amount Of Water For The Moon Cactus?

The suggested amount of water for the Moon Cactus is every 14 days (2 weeks) during the spring and summer. Most cacti don’t need that much water since they are tolerant to drought.

During the winter, you shouldn’t water them too often since they go dormant during those seasons, go ahead and back your watering down to just once per month and that should be fine.

What Is The Best Sunlight For The Moon Cactus?

The best sunlight for the Moon cactus is indirect or partial sunlight. To prevent your cactus from scorching and dying, place it in bright shade such as a covered patio.

What Is The Best Temperature For The Moon Cactus?

The best temperature for the Moon Cactus is 64°F to 77°F (18 – 25°C). Since the Moon Cactus is not cold hardy, anything below 30°F (-1.1°C) is considered freezing for the plant.

If you live in an area that experiences these cold conditions it would be suggested to plant your succulent in a portable pot that can be brought indoors for the cold portions of the year.

How To Propagate A Moon Cactus?

To propagate, you can, with a sterilized cutting tool remove one of the small offsets that are located on top of the cactus, though some Moon Cacti do not have offsets. Carefully remove an offset from the cactus and let it dry out for 1 to 2 days before placing it in well-drained soil.

You can also try extending the life of your Moon cactus by grafting it to a new root stock which would be your only alternative if yours has no offsets.

Is The Moon Cactus Toxic To Humans And Pets?

The Moon Cactus is not poisonous to humans or animals. However, if a large amount is ingested, vomiting or diarrhea may ensue as the plant has a very aggressive fiber structure that can irritate your digestive system.

cat dog

Is The Moon Cactus Edible?

The red plump tops of the Moon Cactus are sweet and edible. To eat, you must remove the tops and cook it to soften it up and be able to remove the hairs and spines.

Why Are There Black Spots On My Moon Cactus?

The black discolored spots on your Moon Cactus can be a sign of a fungal or bacterial infection caused by over watering, low temperatures, high humidity, or not enough light. These can be reversed by taking care of the causes properly.

If over watered, let your cactus dry out completely before watering it again.

If its due to a low temperature, keep your cactus in a warm place from 64°F to 77°F (18 – 25°C).

If it’s because of high humidity, move your cactus or change the humidity to between 40%-60%.

If your cactus is not getting enough light, put it out in the sun for a few hours and then put it back into bright shade to prevent from scorching or drying out.

Why Are There White Spots On My Moon Cactus?

If you see white fuzzy spots on your Moon Cactus, it probably has mealybugs. To get rid of these pests, spray rubbing alcohol on your cactus diluted by adding 50 percent water.

What Are The Common Diseases And Pest Of A Moon Cactus?

While there are no diseases that are known to directly affect the Moon Cactus, spider mites or mealybugs might attack your cactus.

You can prevent the pests from attacking by using insecticidal soap and you can get rid of spider mites and mealybugs by spraying your plant with diluted alcohol as spoken of above.

Why Is The Bottom Of My Moon Cactus Rotting?

The bottom of your Moon Cactus is rotting because of over watering, poor water drainage causing standing water, or possibly both. If the bottom of it is brown and mushy, then it’s the end for your cactus.

Luckily, you can propagate the offsets on top of the cactus. Just carefully remove them and leave them out to dry for 1 to 2 days before planting it in a pot of well-drained soil.

What Is The Life Span Of A Moon Cactus?

The Moon Cactus has a shorter life span than regular cacti that can live from 10 to 100 years. This cactus is grafted and will only live for a few years because of the root stock outgrowing the top of the plant.

sands of time

Why Are My Moon Cactus’ Color Fading?

Your Moon Cactus is discoloring from stress or strain. The problem can be from not enough sunlight, bad watering habits, high humidity, or cold temperatures. By figuring out which of these is the problem, you can render proper care to the plant until the color has come back.

Is The Moon Cactus An Indoor Plant Or An Outdoor Plant?

The Moon Cactus is both an indoor and outdoor plant and the routine of caring for the plant doesn’t change whether it’s indoors or out.

Why Is My Moon Cactus Dying?

Your Moon Cactus is most likely dying because of too much neglect or too much care. This means that it can be getting not enough sunlight or too much, high humidity, cold or too hot temperatures, over or under watering, the list can go on. The Moon Cactus may thrive off of neglect, but fully neglecting or took much care can kill the plant.

Review the earlier care sections in this article to see just how easy it is to remedy the problem.

Why Is My Moon Cactus Growing Arms?

It is normal for your Moon Cactus to grow an arm because of its grafted nature. Moon Cacti are grafted together from a Hylocereus, which are vine-like plants that grow with dragon fruits handing from the arms and tendrils.

 It is perfectly fine if your cactus grows arms, it’s just a trait from the plant it was crossbred with.

How Big Does a Moon Cactus Grow?

The Moon Cactus can grow up to 12 inches (30.5 cm).