All You need to know about Moon cactus

Moon cactus, also known as Gymnocalycium mihanovichii, is a small cactus that is popular as a houseplant. It is native to South America, particularly Argentina and Uruguay.

What makes this plant unique is that it is actually a mutant cactus that lacks chlorophyll and cannot produce its own food through photosynthesis. As a result, it is often grafted onto a rootstock cactus, such as Hylocereus, to survive.

How to grow and take care of moon cactus?

Moon cactus (Gymnocalycium mihanovichii) is a colorful and unique cactus that is easy to grow and care for. Here are some tips on how to grow and take care of moon cactus:

  1. Soil: Use well-draining cactus soil or mix regular potting soil with sand or perlite to improve drainage.
  2. Light: Moon cacti need bright, indirect sunlight. Place them near a south-facing window or under artificial grow lights.
  3. Water: Water moon cactus when the soil is dry to the touch, but do not overwater. Water less frequently in the winter when the plant is dormant.
  4. Fertilizer: Moon cactus does not require fertilizer, but you can feed them with a balanced, water-soluble fertilizer once a month during the growing season (spring and summer).
  5. Temperature: Moon cactus prefers temperatures between 60-85°F (15-29°C).
  6. Propagation: Moon cactus is a grafted plant, meaning it is two cacti grown together. To propagate, cut off the top colorful cactus and let the wound dry for a day. Then, place the top cactus on a new rootstock, such as a new moon cactus or a Hylocereus cactus. Allow the new plant to root and grow.
  7. Pests and diseases: Moon cactus is relatively pest-free, but can be susceptible to mealybugs and scale insects. Treat with insecticidal soap or neem oil. Watch out for root rot caused by overwatering.

Following these tips will help you grow and take care of your moon cactus successfully.

What is the lifespan of Gymnocalycium mihanovichii?

Generally, moon cacti can live for about 8 to 9 years to a decade or more with proper care. However, since moon cacti are typically grafted plants, the colorful top part of the cactus is actually a mutant form that cannot survive on its own.

Therefore, the lifespan of the moon cactus will depend on the lifespan of the rootstock on which it is grafted. With proper care, the rootstock can live for many years, allowing the moon cactus to survive and thrive for a long time.

How to water it?

Moon cacti require less water than many other houseplants and cacti, but it is important to water them properly to ensure they stay healthy. Here are some tips on how to water your moon cactus:

  1. Frequency: Water moon cacti only when the soil is dry to the touch. Avoid overwatering as it can lead to root rot, which can be fatal for the plant.
  2. Amount: When watering, add enough water so that it flows out of the drainage holes at the bottom of the pot. This will help flush out any built-up salts or minerals in the soil.
  3. Water quality: Use room temperature or tepid water, as cold water can shock the roots. If possible, use rainwater or distilled water, as moon cacti are sensitive to high levels of minerals and salts in tap water.
  4. Soil type: Moon cacti prefer well-draining soil that dries out quickly after watering. Use a cactus-specific potting mix or mix regular potting soil with sand or perlite to improve drainage.
  5. Seasonal changes: During the growing season (spring and summer), you can water your moon cactus more frequently. Reduce watering during the dormant season (fall and winter) when the plant is not actively growing.

Remember, it is always better to underwater moon cacti than overwater them. By following these tips, you can keep your moon cactus healthy and thriving.

How to prune it?

Moon cacti generally do not require pruning as they grow slowly and maintain their shape well. However, if you notice any damaged or diseased parts, you can remove them to keep your plant healthy. Here are some tips on how to prune your moon cactus:

  1. Sterilize your pruning tools: Use sharp, clean scissors or pruning shears and sterilize them with rubbing alcohol or a solution of one part bleach and nine parts water. This will help prevent the spread of disease.
  2. Identify the part to prune: Carefully examine your moon cactus to identify the part that needs to be pruned. If you see any brown or black spots, soft or mushy areas, or signs of insect damage, these are good candidates for pruning.
  3. Make the cut: Cut the damaged or diseased part of the moon cactus with a clean, sharp tool. Make the cut as close to the healthy tissue as possible. If the entire top colorful cactus is damaged, you may need to remove it completely.
  4. Let the wound heal: After pruning, let the wound dry for a day or two before watering your moon cactus again. This will help prevent moisture from entering the wound and causing rot.

By following these tips, you can keep your moon cactus healthy and prune any damaged or diseased parts as needed.

How big does Moon cactus grow?

Moon cactus (Gymnocalycium mihanovichii) is a small cactus that typically grows up to 3 inches (7.6 cm) in diameter and 3-4 inches (7.6-10 cm) in height. However, the colorful top part of the moon cactus is actually a mutant form that cannot survive on its own, so it is usually grafted onto a hardy rootstock.

The size of the rootstock can vary, but it can grow up to 12 inches (30 cm) in diameter and 6-8 inches (15-20 cm) in height. The colorful top of the moon cactus is usually smaller than the rootstock and can range in size from 1 to 2 inches (2.5 to 5 cm) in diameter. Overall, the size of a moon cactus will depend on the size of the rootstock, as well as the growing conditions and care it receives.

Which soil is the best for growing it?

Moon cacti prefer a well-draining soil mix that is formulated specifically for cacti and succulents. Here are some tips on choosing the best soil for your moon cactus:

  1. Choose a soil mix that is specifically formulated for cacti and succulents. These mixes are typically made up of a blend of materials like sand, perlite, vermiculite, and peat moss that provide excellent drainage and aeration.
  2. Avoid heavy or clay soils that retain moisture and can lead to root rot.
  3. If you prefer to make your own soil mix, use a combination of coarse sand, perlite, and potting soil. A common recipe is a 1:1:1 mix of potting soil, sand, and perlite.
  4. Before planting your moon cactus, make sure the soil mix is well-draining by testing it out. Water the soil and make sure the water drains quickly through the pot’s drainage holes.
  5. Moon cacti are sensitive to high levels of minerals and salts in tap water, so consider using rainwater or distilled water when you water your plant.

Remember to repot your moon cactus every few years to refresh the soil and give the roots more room to grow. By choosing the right soil mix, you can provide your moon cactus with the right growing conditions to keep it healthy and thriving.

Where can I buy it?

Moon cacti (Gymnocalycium mihanovichii) can be purchased from a variety of sources, both online and in-person. Here are a few places where you can buy moon cacti:

  1. Online plant retailers: Many online plant retailers offer a wide variety of cacti and succulents, including moon cacti. Some popular online plant retailers include Etsy, Amazon, and The Sill.
  2. Local plant nurseries: Check out local plant nurseries in your area that specialize in cacti and succulents. They may have moon cacti available for purchase, and you can see the plants in person before you buy.
  3. Garden centers: Larger garden centers may also carry moon cacti, especially during the spring and summer growing season.
  4. Cacti and succulent shows: Many cities host cacti and succulent shows and sales, which are a great place to find a variety of unique and rare plants, including moon cacti.

Before purchasing a moon cactus, make sure to do some research on how to care for it properly to ensure that it will thrive in your home or garden.


In this post, we discussed moon cacti (Gymnocalycium mihanovichii) and how to care for them. We covered various topics, including the plant’s lifespan, watering requirements, soil mix, pruning, and where to buy them. Moon cacti are small cacti that require well-draining soil, bright but filtered light, and infrequent watering. They are usually grafted onto a hardy rootstock, and the colorful top part is a mutant form that cannot survive on its own. To care for a moon cactus, it is important to choose the right soil mix, water it sparingly, and provide it with bright but indirect light. Pruning is generally not necessary, but you can remove any damaged or diseased parts with clean, sharp tools. Moon cacti can be purchased from a variety of sources, including online plant retailers, local plant nurseries, garden centers, and cacti and succulent shows.

Have a nice day!

Ari Iniesta

Ari Iniesta

Total posts created: 199
Hello fellow succulent enthusiast! My name is Ari Iniesta, and I'm a succulent enthusiast. I was born and raised in a small town in southern Spain, where the warm climate and dry conditions allowed me to develop a love for plants that are able to thrive in harsh environments. As I got older, my interest in succulents only grew stronger. I began to study horticulture and botany, and I even started my own collection of rare and exotic succulents from around the world.

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