Moon Cactus Growing Arms, Propagation, Care, Grafting

Moon Cactus is a grafted plant which basically means two plants are combined in such a way they share water and nutrients with each other. In this Succulent we have Scion which is top part of gymnocalycium mihanovichii and the lower part is hylocereus cactus which is a cactus plant used for grafting Scion to make a ruby ball cactus or moon cactus.

The Lower portion cactus has a job to provide nutrients and water to the top succulent portion. Lower cactus is green in color which makes the food, but the scion doesn’t have green pigment of chlorophyll to make any food, that is why it needs a green cactus which can provide it nutrients.

This succulent can grow and survive for many years as both portions have different rates of growth. The Lower part is called rootstock. The Upper part scion cactus has tiny baby cactus that can be propagated or grafted. This red top cactus can only be grafted for its survival , grafting is done because they don’t have any green pigment which makes their food , so without rootstock they won’t live any longer.

gymnocalycium mihanovichii Moon Cactus care growing
SKsiddhartthan, CC BY-SA 4.0, via Wikimedia Commons

Specification :

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Family Cactaceae
Scientific Name Gymnocalycium mihanovichii
Other Names Red Cap, Ruby Ball Cactus,Hibotan cacti and Red Hibotan
Native South America
Plant Type Perennial
USDA Hardiness Zone  11, 12
Flower Color Red, Pink, Yellow, Orange
Soil Cacti Mix & Well Drained
Water Little Bit Depend on Moist
Light Partial Shade
Fertilizer Not Required But Used

(Red Ball) Moon Cactus Care

If you are ever growing cactus or any other succulent plants than Growing and Caring of this Moon Cactus can be an easy task and mostly they were used in many cacti gardens for their beauty and uniqueness.

What’s Different in these plants is they basically lose the green color and are termed as albino plant means which has no chlorophyll content in it which makes the green leave color. 

They were mostly called as grafted cactus – means some other plant species has been attached to the wounded area of another. This is why both the bottom and top portion needs to have good relationships, otherwise it will die.

Same as cactus, the care is very similar and if you want to grow moon cactus then follow the below mentioned points. These plant soil needs to be dry before watering otherwise leaves might get pale or wilt. It is always advised to keep this lightly moist and not soggy in soil, any excessive water that stays longer on the soil can result in root rot. This issue alone has a very bad impact on the whole cactus, But still Cactus are not an easy plant , they tolerate much more things easily so they are strong.

Let’s Check Ruby Ball Cactus Care:


According to NDSU , For these types of succulents , cactus soil is best performer with sand, But that was not easy to find in nursery or its stock out as many people have cactus type succulent in their house and every guide suggested that potting mix. Link for Cactus Potting mix.

Another option is peat based potting mix that will also work. Link for peat potting mix.

It’s your choice whether you can use any potting mix with sand, make sure to mix 50% of both material. & additionally if you drop 15-20% gravel to increase its drainage that can be best.


Moon cactus like to be in a partial shade area or where there is indirect sunlight. These plant can also grow in shade place and dislikes the direct sunlight. If they get direct sunlight it would be bad for the cacti plant. Cactus which grow in harsh sunlight in desert locations have green stems in them and for moon cactus variety it is very important for you to know the right knowledge for its light requirements.

The East , West Window facing Area gets bright sunlight in the morning and some direct sunlight but it can be tolerable. For a South facing room , you need to put your plant near the window but make sure it doesn’t get direct sunlight for many hours otherwise leaves get burned and immediately it will feel water need. 

Leaves turning yellow may have a reason for overwatering and heavy sunlight. Issues regarding spots , scars , burn signs then make sure to change the location of your succulent to some other shade place as the plant is getting too much sunlight. The best location would be in partial shade where it gets morning 2-3 hours direct sunlight and after that sun moves so indirect sunlight will do the job and it will not harm the plant.


These cactus plants like warm places and locations where the temperature is hot, and you know every cactus favorite location is desert. Moon cactus can grow indoor with room temperature. Growing condition for both of the upper and lower portion of this plant is not same, the scion(upper part) grows in USDA zone 11 and 12 while the rootstock(bottom) variety have USDA hardiness 9 and 8 or below this zone. 

According to NDSU , In winters it is preferred that 45-55 F is the temperature they should be kept in and not below this. Otherwise they can thrive in over 80-90 F. What you can do indoors is have a regular temperature so make sure not to open windows as the freezing air can be harmful. By following these tips your plant can survive.


Just like other succulents and cactus , this variety can handle the drought climate. When You should water moon cactus is when it feels dry , check the soil using pencil for moisture if it’s wet then check the next day. There is no need to overwater your beautiful plant when they don’t need it. Once you see it is completely dry , Make sure to water it fully so the water drains out from the base.

Also it’s good to check the pot holes sometimes if they get blocked with hard soil at bottom , it gives plants a new problem of developing root rot.

How Often you should water your moon cactus? So basically it all depends on the climate and how warm or cold the temperature is in your place. In Summer , Once a week is enough but still you have to check soil before watering. When we talk about winters you shouldn’t water it or spray on the root base after 15-20 days if it’s clearly dried out.

Spraying some water will help them to be healthy in winters. This season you shouldn’t excess water as there is a fungal and root rot problem that results in plant leaf wilt and then it dies.  

Succulent never requires excess water, but if it was not given water for like 3 weeks then do give water to all corners and it should drain out properly so using a good quality soil is also preferred.


Moon cactus can tolerate low to moderate levels of humidity and it is the same as other succulent and cactus in this moisture needs. What is required and always be aware of is not to make it heavy moist , they can handle the dryness but not overwatered soil. 

To make sure their top part stays healthy we need to moisturize it by spraying water on it from time to time. When in winters watering has been stopped but we can still spray some water to make sure it doesn’t lose growth although they are mostly in dormant period.

Start water normally once winter is over and you can see the climate is now warm. Also sometimes put them outdoors, for freshness. But use pesticide for any infestation before moving indoors.


So You have brought the plant now before repotting it in your current pot, make sure to check if that pot is larger than the original pot that succulent came in, because this plant needed some to spread.

You should also check bottom holes in the pot so that there is no issue on drainage of water.

Don’t Remove the soil which comes with the plant, just drop that in the new pot and before that you should put some potting mix , make sure the root doesn’t go too deep.

Problem also comes in when people don’t select a good sized pot , if you choose a very bigger size pot then it will make the soil soggy and wet. This creates another problem called root rot which is harmful for plants.

Problems/ Pests and Diseases

Moon cactus is strong , colorful and can tolerate many climatic conditions. One Problem that it gets from mealybugs is it keeps sucking the plant sap & weakens and the other bug is spider mites which suck the fluids on the leaves and this makes white spots which look ugly. To get rid of these 2 pests we recommend using 

Disease is only that root rot which happens because of too much water. Rotting issues can kill the plant if not solved. One such solution is not to overwater your plant and in winter only spray some water and make it healthy.


Moon Cactus generally don’t need additional plant food or fertilizer , But giving them in the growing season can make them more healthy and colorful. The time from fertilization is from April to September and it is advised that don’t give any plant food in freezing times like winters.

We have suggested the best fertilizer for Your cactus.

Read More : Here is the Article you can check best fertilizer for Succulent

Graft moon cactus

Before Propagation , You need to understand grafting : There are basically many cactus you can use to graft a moon cactus but 3 of them are approved and one of them is Hylocereus trigonus. Also if they live in the same family species that would be great to successfully grow this succulent.

In Short , what you need is a lower portion of this green cactus and upper or scion of gymnocalycium. Now you need to cut the green cactus from top and check if the white circle portion is visible.

same thing you need to do with the scion and take a thin slice moon cactus and see if the white portion is visible. now you are ready and join both the cactus portion and make sure the center portion is perfectly join. Use a rubber band and don’t remove it for 2 weeks.

After 2 weeks you can check , they will be attached and started growing.

Also SEE  : I will explain detailed article on How to graft cactus.

Moon Cactus Propagation

Moon Cactus gymnocalycium mihanovichii
SKsiddhartthan, CC BY-SA 4.0, via Wikimedia Commons

From the above picture you can see there are white spines are coming these are called baby scion and they are used in making a new moon cactus plant. The Same process above applied here also and you need another green healthy cactus and sharp cutting tool to slice the moon cactus from base.

Propagation is easy but still it requires you to follow guide otherwise it might live but will end up growing slower , It happens when people didn’t place the scion at the center of green cactus.

I am giving a grafting video so you can become expert in doing propagation & don’t make mistake. Its kind of unique process just like this cactus is.

Most Searched Questions:

Moon cactus flower

These plants come in many different colors and sizes , even the shapes are different. When the flower is growing you will see its own stem opening upward. Moon cactus flowers come in yellow , purple , pink, red and most sold in nursery and online are yellowish or reddish colored cactus.

Moon cactus dying

This problem happens with everyone when the moon cactus starts losing its colors and looks wilted. If the whole moon cactus top part (scion) turns brown and looks pale then remove that with the Blaze and sterilize it before that. The green cactus will grow without it. 

Now if your scion’s lower portion is losing color then you must slice the part and again graft it in the rootstock(green cactus) , It will survive.

There is also one thing to note about these cacti: they don’t live for long and eventually die so if you are thinking it’s your fault for not caring then it is wrong as these are made for a few years not lifetime.

Also Make sure you try to spray water only and not pour it in the soil. Spray some water on the scion, rootstock and the root base, it’s the advice I can give otherwise they don’t live a longer life.

Moon cactus pups

These are the small baby moon cactus that grows in the scion at the top of it. You can propagate moon cactus from these small pups. Grafting is the same for these but wait for them to grow bigger so you can take slices from the lower end pups. they can be placed in the green cactus or rootstock. So many pups are developed on the scion which is good for us, if our plant dies we can still use these. 

Moon cactus bloom

These cacti are available in different colors and it needs minimum care and a small can to do the work. Moon cactus generally blooms in the end of the spring or we can see flowering in early or mid summer.

Moon cactus lifespan

According to NPS, Saguaros is also a cactus that was only 1.5 inch in 8 years & the average lifespan they live is 150-175 years. When it comes to the moon cactus can be alive for 5-90 years, But mostly they have started losing colors and show signs of dying so I can’t confirm the actual lifespan if the caring is good they can live for few years.

Moon Cactus top rotting

Rotting is connected with watering and once you pour water it needs air to dry. If it doesn’t dry out then you may see the lower scion rot and that is the top of the moon cactus. Make sure to remove the lower rotted slice and replant it using a grafting method. Check the whole process and video above to understand & before anything do sterilize the knife or things you are going to use to cut the part.

Moon cactus growing arms

The “arms” you are seeing on your moon cactus are likely new growths from the rootstock. When the rootstock, which is the plant onto which the moon cactus is grafted, begins to develop its own branches or arms, this happens. Although this development often indicates that the rootstock is strong and prospering, it may also indicate that it is depleting the resources of the moon cactus that has been grafted on top.

Pruning these limbs off will preserve the moon cactus’ natural look. They will ultimately develop into entire branches of the rootstock cactus if you let them continue to grow. Remember that the branches may vary from the rest of the plant since the rootstock cactus is probably a different species from the moon cactus. It’s also critical to be aware that the grafted moon cactus may ultimately lose its visibility due to the rootstock’s development, which might result in its demise.

It’s important to note that the moon cactus itself may sometimes produce additional growths, however this is less often. The moon cactus itself is most likely the source of the new growths if they share its hue.

Keep in mind that grafted cacti need bright but indirect light, watering only when the soil is totally dry, and maintenance at a temperature of between 70 and 80 degrees Fahrenheit. If you are unclear about the growths on your moon cactus, please seek advice from a nearby nursery or a cactus/succulent specialist.


How big does a moon cactus get?

The height of the moon cactus is about 4 inches and the width can be around 1 to 2 inch. how big it would grow also depends on rootstock and this length can vary but after growing 10 cm they will not grow. If you give good care you might see them growing healthy. 

Can you plant Moon Cactus babies?

They can only be planted in rootstock and will not grow without any green cactus. You will just make your plant die if you plant these babies directly in soil. These are grafted varieties and they never grow without lower cactus.

Are moon cacti poisonous to cats?

This plant belongs to the Cactaceae family , and Cactus is not toxic plant ingestion but we don’t have any source to claim this so we advise you until there is a good report on moon cactus this plant can’t be considered as toxic or non-toxic. They have spines that you and the cat need to stay away from they can give irritation to skin.

If any issue happens please call the pet center or hospital immediately.

Is Moon Cactus indoor or outdoor?

This plant is generally grown indoors and thrive best inside the house because it gets a clean environment without pests and the moon cactus needs bright light not direct light so indoor has indirect light. Even Winters you can grow them inside as the temperature is ideal , but outdoors it’s too freezing. Outdoor there are other issues regarding diseases, and basically this plant is not too big , it takes small space so it’s best indoors.


Its a unique cactus grafting and growing experience if you have one and want to grow them.

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Amelia Clark

I'm Amelia Clark , a seasoned florist and gardening specialist with more than 15 years of practical expertise. Following the completion of my formal education, I dedicated myself to a flourishing career in floristry, acquiring extensive understanding of diverse flower species and their ideal cultivation requirements. Additionally, I possess exceptional skills as a writer and public speaker, having successfully published numerous works and delivered engaging presentations at various local garden clubs and conferences. Check our Social media Profiles: Facebook Page, LinkedIn, Pinterest, Youtube, Instagram Tumblr

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