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Red Cap Cactus

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  • Light Preference/Tolerated (Bright Direct Light)
  • Low Watering Needs
  • Mature Height 6-12 inches
  • Pet Safe

Where the Red Cap Cactus (Gymnocalycium mihanovichii var. friedrichii "Rubra" graft) can be seen in garden centers and grocery stores alike, few understand just how interesting this colorful cactus is. The red top of the cactus, often confused for a flower, is a separate species that lacks chlorophyll, giving the plant its fiery ruby color. Because these beautiful mutants cannot survive on their own, they are expertly grafted onto another green cactus species that provides nutrients and energy to the whole plant. These easy-to-care-for succulents require infrequent watering and are an eye-catching addition to a bright space.

Best Locations For Growing Red Cap Cactus 

Like other cactus and succulent plants, the Red Cap Cactus, also called Moon Cactus, will thrive in a spot that receives plenty of bright light, even tolerating direct sunlight. Pair the Red Cap with other succulents and cacti in a planter and admire its bright color and unique shape. These small plants fit nicely in a kitchen windowsill or on a patio tabletop as well. 

Red Cap Cactus Sunlight Requirements

Place the Red Cap Cactus in a warm spot where it can get bright light most of the day, such as an east-facing window. This cactus can tolerate direct sunlight from a south- or west-facing window, though it may need protection from intense afternoon sunlight. Some signs that the light is too bright include fading color, called bleaching, and white or brown sunburn scabbing. Cacti are not typically tolerant of medium to low light, and the Red Cap Cactus is no exception. Low light levels may lead to etiolation (stretching toward light), loss of color, and an increased risk of root rot. 

Red Cap Cactus Care

Cacti and succulents prefer to be in smaller, tighter pots with less excess soil around their roots. This allows them to dry out more quickly and fully in between waterings. For this reason, the Red Cap Cactus can stay in the same pot for years without needing additional space to grow. When you do decide to repot, choose a pot that is only an inch or two larger in diameter and with plenty of drainage. Cacti do best when planted in well-draining cactus or succulent soil. 

Watering Red Cap Cactus

Cacti and succulents are able to store water in their stems. Because of this, it is a lot easier to overwater a cactus than it is to underwater it. Allow the soil of the Red Cap Cactus to dry out completely before watering deeply and fully. You may have to add water a few times before the soil refills the pot and holds onto water. In warmer months, you may need to water as much as once or twice a month depending on lighting, temperature, and humidity. In winter, cut back on watering significantly, only watering when the soil has completely dried. 

Feeding Red Cap Cactus

The Red Cap Cactus will appreciate light fertilization in the spring and summer months. Use a cactus and succulent-specific fertilizer once a month while the plant is growing. Fertilizing in the winter is not necessary as indoor plants typically slow down their growth significantly.

Red Cap Cactus Information

Light Exposure: Bright Direct Light
Care Requirements: Easy
Watering Requirements: Below Average - Let the soil dry completely, then, water deeply.
Pet Friendly: Yes
Kid Friendly: Yes
Air Purifier: High
Habit: Clumping
Growth Rate: Slow
Mature Height: 6-12 inches
Mature Spread: 2 inches
Flowering: Yes
Flower Color(s): Pink, Purple
Flower Shade/Description: Pale-Pink to Purplish-Pink
Fragrant: No
Foliage Type:
Foliage Color(s): Green, Pink, Red
Foliage Description: Green/Red/Pink
Temperature: 25° - 50°F (-4° - 10°C)
Humidity: Low
Common Name: Red Cap Cactus
Other Name(s): Ruby Ball
Scientific Name: Gymnocalycium mihanovichii var. friedrichii "Rubra"
Plant Type: House Plant

Container Sizes

Please Note: The pictures below are to give a general representation of the different container sizes. The actual size/ages of plants are estimates and will vary based on; type of plant, time of year, last pruning & many other factors.

4.5 Pot

4.5" Pot
 Also Known As:
   4.5" Container

 Plant Age:
   ~ 6 months
 Plant Size:
   ~ 3"-6"
 Pot Size:
   ~ 4.5"H x 3.75"W
   1.42 quarts

Quart Pot

Quart Pot
 Also Known As:

 Plant Age:
   ~ 6 months - 1 year
 Plant Size:
   ~ 4"-8"
 Pot Size:
   ~ 4.75"H x 4.5"W
   1.50 quarts

2.5 Quart

2.5 Quart
 Also Known As:
   2.5 Quart Pot

 Plant Age:
   ~ 1 - 2 years old
 Plant Size:
   ~ 8"-12"
 Pot Size:
   ~ 6.5"H x 6.5"W
   2.20-2.30 quarts

#1 Pot

#1 Pot
 Also Known As:
   #1 Container
    1 Gallon
 Plant Age:
   ~ 1 - 2 years old
 Plant Size:
   ~ 10"-14"
 Pot Size:
   ~ 7"H x 7.75"W
   2.26-3.73 quarts

#2 Pot

#2 Pot
 Also Known As:
   #2 Container
    2 Gallon
 Plant Age:
   ~ 1.5 - 3 years old
 Plant Size:
   ~ 12"-18"
 Pot Size:
   ~ 9.5"H x 9.5"W
   1.19-1.76 gallons

#3 Pot

#3 Pot
 Also Known As:
   #3 Container
    3 Gallon
 Plant Age:
   ~ 2 - 4 years old
 Plant Size:
   ~ 12"-30"
 Pot Size:
   ~9.5"H x 11"W
   2.32-2.76 gallons

For more detailed information, please click here.

Plant Addicts Guarantee (Included On All Plant Orders)

Plant Addicts always guarantees your plant(s) will arrive happy & healthy. However, plant(s) are being shipped through the mail & sometimes accidents happen. If the plant is dead, has dried out roots or the incorrect item was shipped, just notify Plant Addicts within 3 days upon delivery. We may ask for pictures but will try to make it as easy as possible for you. Please note, plant(s) with damaged branches or wilted leaves will not qualify for this guarantee. Plants are very resilient and will rebound quickly when cared for correctly. 

For more information on how to care for your new plants, please click on our guide below.

Guide: How to Care for Your New Plant(s)

Plant Addicts Warranty - 1 Year (Extra Purchase Required)

We encourage all plant lovers to purchase the Plant Addicts Warranty, whether you're a new gardener or an expert. There are many variables outside of anyone's control that can cause a plant to die. Hungry animals, drought, poor soil conditions, over watering, diseases & pests are all good examples of what can cause plants to die. The Plant Addicts Warranty is a 1 year warranty protecting you from all of the unknowns and will replace your plant if something were to happen to it.

The warranty is purchased on a per plant basis and must be purchased at the same time as the plant(s). We will cover 100% of the price of the plant, but the warranty does not cover shipping costs. SImply let us know if your plant has died within 1 year of receiving it and we will get you a new one shipped out as soon as possible (depending on the time of the year and availability). We may ask for photos for documentation purposes, but we try to make the process as easy as possible.

For more information, please click on our page below.

Guarantee and Warranty

Plant Shipping

Below are some factors we consider when determining when to ship the plants depending on the timing of the order.

Winter to Early Spring

We ship only when it's warm enough to plant in your growing zone.
Sometimes plants aren't completely ready to sell and ship in early spring. We will wait until the plants are ready before shipping so you don't get a subpar product.
For Southern plants we will be able to ship much earlier than plants coming from our northern nursery.


If there is extreme heat we may delay shipping for a week or several weeks.
We review what areas the plants are traveling through as well as your location.

Fall into Winter

We’ll ship plants out all the way up to the end of the fall planting season!


Get your order in early to reserve your plants for Spring planting!

Once your plant is shipped you’ll receive an automated email with tracking information. 

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Planter Shipping

Standard Colors: 2-3 business days

Special Order Colors: 8 weeks - this is due to the planter being custom made with the color(s) of your choice

Please Note: On special orders there can not be any cancellations