Brainy Gardener

    Subscribe to Updates

    Get the latest creative news from FooBar about art, design and business.

    What's Hot

    Botrytis Blight: How to Recognize, Treat and Prevent the Gray Mold

    January 28, 2023

    Solving the Powdery Mildew Puzzle: How to Protect Your Houseplants

    January 28, 2023

    Crassula Red Pagoda: Growing And Care Guide

    January 27, 2023
    Facebook Twitter Pinterest
    Brainy Gardener
    • Home
    • Houseplants
    • Succulents and Cacti
    • Bromeliad
    • Contact
    Brainy Gardener
    Home»Succulents and Cacti»Moon Cactus (Gymnocalycium Mihanovichii) Indoor Care Guide

    Moon Cactus (Gymnocalycium Mihanovichii) Indoor Care Guide

    Moon Cactus: Two Cacti into One!
    By Milo MasonDecember 21, 2022
    Share
    Facebook Twitter Pinterest Email

    Moon Cactus is a special cactus grown from grafts of two different cacti. The Hylocereus is the rootstock, and the Gymnocalycium mihanovichii is the scion. These two different cacti are grafted together, and their union is collectively referred to as a Moon Cactus. They are also known by Ruby Ball Cactus, Red Cap Cactus, and Red Hibotan, to name a few. 

    Moon cacti are prized for their unique appearance, and they can be found in many different colors. They are primarily grown indoors in a pot and serve as houseplants requiring little maintenance.

    The key part is the colorful scion, which is always a variant of Gymnocalycium mihanovichii species. The rootstock is a choice between many different types of cacti, with Hylocereus being the most common. The rootstock’s two jobs are to prop up the scion to display its unique coloration and provide its chlorophyll capabilities. Gymnocalycium mihanovichii display different colorations than typical cacti because of their lack of chlorophyll. This means that they cannot survive on their own for any length of time; this is where the rootstock comes in. It is a parasitic relationship between the two, with the rootstock usually ending up discarded in favor of fresher stock further down the line.

    Moon Cactus Main Characteristics

    Common NameMoon Cactus, Ruby Ball Cactus, Red Cap Cactus, Red Hibotan, Red Cactus
    Botanical NameGymnocalycium mihanovichii
    SynonymsEchinocactus mihanovichii, Gymnocalycium friedrichii
    FamilyCactaceae
    GenusGymnocalycium
    TypeCactus
    Native RangeParaguay, Northeast Argentina
    FoliageEvergreen
    Propagation methodsRegrafting, Offsets
    SunFull sun to partial shade
    SoilWell-drained
    ToxicityNon-Toxic

    Moon Cactus Care

    The grafted specimen of Gymnocalycium mihanovichii and Hylocereus are a popular choice for collectors. These plants are relatively easy to care for and have a striking appearance. Care for them like any other cactus despite their unusual nature, and you’ll succeed. Here’s how to get started.

    Moon Cactus Care
    Moon cactus care

    Light and Location

    Moon cacti do best when placed in a location that receives bright, indirect light with a few hours of sun each day. So, if you’re growing them indoors (as you should), find a spot near a window where they will receive the right amount of light. 

    Note that these are two different cacti grafted together; the top portion likes a bit of shade while the bottom wants direct sun. Compromising between the two is necessary for the plant to function. 

    Watering

    Water your Moon Cactus deeply but allow the soil to dry out between waterings. Overwatering results in root rot and death. An excellent way to test is to stick your finger in the soil. If it’s wet, don’t water it yet. Be mindful that, like many others, this cactus doesn’t need watering in the winter; mist the leaves if the cactus looks like it needs some water but nothing more.

    Temperature

    Moon Cactus prefers intermediate temperatures. Make sure you don’t place it in a spot where it will get too hot or too cold. The room temperature is usually just fine.

    Humidity

    Gymnocalycium mihanovichii enjoy a dry spell as much as the next cactus, so keeping them in low humidity spots is a given. But remember to mist the plant in the winter as it’s the only moisture it can tolerate during dormancy.

    Fertilizer

    Feed your Moon Cactus a balanced fertilizer diluted to half-strength every month during the growing season. These plants don’t need it per se, but it will help. Like watering, don’t bother with feeding in the winter as the cactus goes dormant.

    Cultivars of Gymnocalycium mihanovichii

    There are a few different cultivars of Gymnocalycium mihanovichii, but the most popular is the Ruby Ball Cactus or Red Hibotan. This cactus looks like a round, ruby-colored ball that looks gorgeous mounted on a green stalk. It’s one of the more visually appealing cacti and makes for a great conversation starter.

    If you’re looking to add a Gymnocalycium mihanovichii to your collection, be sure to get a grafted specimen as they are much more eye-catching than the regular kind. Your Moon Cactus will thrive with the right light, water, and temperature.

    Propagating Gymnocalycium mihanovichii

    Due to their peculiar nature, Moon Cacti can’t be propagated the same way as regular cacti. The only real way to propagate them is by grafting the scion on another rootstock. Grafting is easier than it sounds; here’s how you do it:

    1. Cut off a part of the Gymnocalycium mihanovichii and the top of the fresh rootstock (Hylocereus) with a sharp, sterile knife.
    2. Join the two cut ends of both cacti so that both of their spines meet. The spines are the distinct white center visible on the cut surface.
    3. Secure the two cacti with a rubber band that’s not too loose or too tight.
    4. Wait for about two weeks for the grafting to be complete.

    Sometimes the scion produces offsets or “pups” that can also be grafted. The process is the same as grafting the main body of the scion, but instead of using the main body, you’ll be using the smaller offsets it produces. 

    Potting and Repotting Gymnocalycium mihanovichii

    Moon Cactus doesn’t grow too fast, and it will take a few years before it needs repotting. But, even if the roots aren’t spilling out of the pot, repotting can still be beneficial. It will allow the plant to experience fresh soil filled with nutrients. 

    You can repot these cacti at any time of year, but it’s best to do it when it’s actively growing. When you do repot, be sure to use a pot that’s one size larger than the pot you’re using now. Use a soil mix that drains well, like a cactus mix. Make a hole in the center of the soil and place the cactus in it. Gently pack the soil around the cactus. Water sparingly until the plant is established.

    Gymnocalycium Mihanovichii In Pots
    Gymnocalycium mihanovichii in pots

    Toxicity

    Gymnocalycium mihanovichii is generally non-toxic to both humans and pets.

    Common Pests

    Mealybugs and scale insects are the most common pests you’ll find on these cacti indoors. If you see any signs, take swift action to get rid of them. Horticultural oils can deal with these pests without damaging the plant.

    Common Problems

    Washed Out Colors

    A common problem is too much light. These cacti need bright, but not direct, sunlight. They can tolerate direct sun, but only a little. If they’re getting too much light, their colors become washed out as a sign of stress.

    The Rootstock Is Tilting

    The most common problem with Moon Cactus is overwatering. Don’t allow the water to stand in the pot, and be sure to only water when the soil is dry to the touch. Overwatering will cause the roots to rot and the bottom cactus to collapse until it eventually dies.

    The Graft Coming Apart

    The place where the two different cacti are connected can come under extreme strain due to the two cacti growing at different rates. This is quite natural, and there is nothing you can do except find a new rootstock. The grafted union of a Moon Cactus comes with a strict time limit.

    Moon Cactus Indoor Care Guide (Video)

    FAQ

    Why Is My Moon Cactus Turning Yellow?

    A yellowing Moon Cactus is usually a sign that it’s getting too much light. Move it to a shadier spot, and the color should return to normal. It could also result from too much water; check your watering routine.

    How Often To Water Moon Cactus?

    Watering every week is usually enough, but check the soil moisture to be sure. When it’s dry to the touch, water thoroughly. In the winter, when the cactus is dormant, don’t water at all.

    Can I Grow Moon Cactus From Seed?

    No, you can’t grow one from seed. These cacti are a result of grafting that doesn’t occur naturally. You need human involvement for this combination to occur. 

    Share. Facebook Pinterest Tumblr Email
    Milo Mason

    Milo Mason is a self-proclaimed plant whisperer. With a passion for gardening, houseplants, and all things outdoors, Milo has been cultivating indoor plants for the past five years with an interest in perennials and succulents. He enjoys sharing his insights and research on plant species when it comes to care tips.

    Related Posts

    Crassula Red Pagoda: Growing And Care Guide

    The Ultimate Defense Against Mealybugs on Houseplants

    Delosperma ‘Wheels Of Wonder – Golden Wonder’: Growing And Care Guide

    Comments are closed.

    Don't Miss

    Botrytis Blight: How to Recognize, Treat and Prevent the Gray Mold

    Solving the Powdery Mildew Puzzle: How to Protect Your Houseplants

    January 28, 2023

    Crassula Red Pagoda: Growing And Care Guide

    January 27, 2023

    Earwigs: Guide To Identify, Control, And Prevent

    January 27, 2023
    About Us
    About Us

    Brainy Gardener is a gardening blog that offers practical, real-life tips and inspiration to help you know how to garden successfully. The website has in depth, well written and clear articles on all sorts of topics and plants, from hydroponics to specific plants like daisies or succulents, houseplants, plant problems

    Email Us: info@brainygardener.com

    Our Picks

    Botrytis Blight: How to Recognize, Treat and Prevent the Gray Mold

    January 28, 2023

    Solving the Powdery Mildew Puzzle: How to Protect Your Houseplants

    January 28, 2023

    Earwigs: Guide To Identify, Control, And Prevent

    January 27, 2023

    Subscribe to Updates

    Get the latest gardening tips from Brainy Gardener.

    © 2023 BrainyGardener.com. All rights reserved.
    • Home
    • Privacy Policy
    • Disclaimer
    • Terms of Use
    • Contact

    Type above and press Enter to search. Press Esc to cancel.