Cacti are commonly grown as houseplants, making ornamental and decorative additions to indoor spaces. Their low-watering needs mean they are a popular, beginner-friendly option. Although they are considered low-maintenance compared to many tropical species, cacti do require plenty of bright light to grow well. When growing a cactus indoors, consider its individual care needs so that it receives the best environment for optimum growth.
Thimble Cactus (Mammillaria gracilis fragilis)
This small, cluster-growing cactus forms mounds of spherical stems with a dense covering of fine, radial spines. When grown in sufficient light, the thimble cactus will produce bell-shaped white or yellow flowers through spring and summer. It requires 6 to 8 hours of bright light a day—next to a west- or south-facing window is a good choice. Consider using a grow light during the darker months to avoid elongated growth.
- Light: Full sun to dappled sun
- Size: Up to 4-6” tall
- Water: Every 1 to 2 weeks
- Dormancy: Winter dormant
Tip: The thimble cactus has spines that grow perpendicular to the stem, meaning it is easier to handle than many other cacti. This makes it a good option for homes with pets and children.
Bunny Ears Cactus (Opuntia microdasys)
As with other Opuntia species, the bunny ears cactus is a popular ornamental houseplant. Its flattened, oval-shaped stem segments are covered in tiny, fine spines. Opuntia microdasys prefers full sun and does best next to a south-facing window when grown as an indoor cactus. Take care not to overwater—Opuntia species are particularly sensitive to wet or waterlogged soils.
- Light: Full sun
- Size: Up to 2-3’ tall
- Water: Infrequent, light watering
- Dormancy: Winter dormant
Tip: Bunny ears is a large indoor cactus that can reach up to 3 feet tall. If necessary, cut back individual stem sections to maintain a more compact size.
Christmas Cactus (Schlumbergera truncata)
The flowering Christmas cactus is a popular indoor cacti species. Tolerant of partial shade, this tropical cactus prefers slightly humid conditions and lightly moist soil. The Christmas cactus typically produces red, pink, or white flowers during the holiday season. Its trailing stems make this plant a good option for containers and hanging baskets.
- Light: Dappled sun or partial shade
- Size: Up to 12” tall and wide
- Water: When the top 2” of soil is dry
- Dormancy: Partial dormancy in mid-fall and late winter
Tip: A bathroom with a bright, frosted window is the perfect location for a Christmas cactus.
Barrel Cactus (Ferocactus spp. and Echinocactus spp.)
Barrel cacti have spherical or cylindrical, deeply ribbed stems with protruding spines. It is a cactus that likes full sun, requiring at least 6 to 8 hours of bright light a day. Grow next to a west- or south-facing window to provide ample sunlight. In low-light conditions, barrel cacti will grow elongated stems and may become pale and stunted.
- Light: Full sun
- Size: Up to 3’ tall
- Water: Every 1 to 2 weeks
- Dormancy: Winter dormant
Tip: Barrel cacti prefer stable conditions—protect from drafts and extreme temperature fluctuations.
Rat Tail Cactus (Aporocactus flagelliformis)
The rat tail cactus is characterized by long, trailing, spine-covered stems. It is a good choice for hanging baskets next to a bright, sunny window. It requires frequent watering through the growing season but prefers to dry out in between.
- Light: Full sun
- Size: Up to 3-6’ long
- Water: Frequent, light watering
- Dormancy: Winter dormant
Tip: The rat tail cactus propagates easily from stem cuttings. Simply cut off a portion of stem, leave to callous for a few days, and plant into cactus soil. Roots should develop after 3 to 4 weeks.
African Milk Tree (Euphorbia trigona)
This plant is actually a succulent, although it is sometimes called cathedral cactus or friendship cactus. Its tall, thorned branches make it well-suited among cactus arrangements. The African milk tree grows slowly indoors and prefers almost completely dry conditions with moderate watering every few weeks. Grow next to a south-facing window and use a sheer curtain to protect against harsh sunlight.
- Light: Partial sun
- Size: 6-9’ tall
- Water: Allow soil to dry completely
- Dormancy: Winter dormant
Note: African milk tree produces a white sap which is toxic to pets and humans.
Moon Cactus (Gymnocalycium mihanovichii)
The moon cactus is a brightly colored, ornamental plant that does well indoors. It consists of two species grafted together, characterized by its red, yellow, pink, or orange tops. The moon cactus is sensitive to harsh sunlight, requiring a bright room that has protection from direct sun. Water sparingly, allowing the soil to dry completely for 5 to 7 days.
- Light: Dappled sun or partial shade
- Size: Up to 12” tall
- Water: Every 2 weeks
- Dormancy: Winter dormant
Tip: There are many different types of moon cactus that offer different shapes, sizes, and colors.
Fairy Castle Cactus (Acanthocereus tetragonus ‘Fairy Castle’)
The fairy castle cactus is a miniature cultivar of Acanthocereus tetragonus. It is made up of numerous, clump-forming vertical stems with short, bristle-like spines. It requires a bright room but should be protected from direct sunlight at hot times of the day. This is an easy-care, compact cactus species that does well as a houseplant.
- Light: Partial sun
- Size: Up to 2-3’ tall
- Water: Allow soil to dry completely
- Dormancy: Winter dormant
Tip: For homes with more space, choose the larger species – Acanthocereus tetragonus (triangle cactus) – that can grow up to 6 feet tall.
Easter Lily Cactus (Echinopsis subdenudata)
This small, almost spinless cactus produces white, fragrant flowers at night during the spring and summer. It prefers full sun but may require protection in intense heat—next to a south-facing window with a sheer curtain is a good location for the Easter lily cactus. Water only once the soil is completely dry.
- Light: Full sun to partial shade
- Size: Up to 3” tall
- Water: Every 2 to 3 weeks
- Dormancy: Winter dormant
Tip: Feed with a potassium-rich fertilizer at the beginning of the growing season to encourage flowering.
Caring for Cactus Plants Indoors
Care requirements will differ between cacti species. Several general rules apply when growing cacti indoors. However, make sure to pay attention to the individual needs of each species to provide the best growing conditions.
Light
Whilst there are some cacti that tolerate shade, most types of cactus need sun and plenty of bright light to grow their best. Choose a location that is no more than 1 foot away from a bright window and use a sheer curtain for species that are sensitive to full sun. Grow lighting is a good option in darker homes and north-facing rooms.
Soil
Cacti require well-draining, nutrient-poor soils. Choose a specialist cactus soil or incorporate at least 50 % perlite, pumice, or sand into a regular mix.
Watering
Most cacti and succulents prefer to dry out between watering and are sensitive to waterlogged conditions. Check soil moisture before watering and allow excess water to drain away.
Humidity
Most cacti are native to arid and semi-arid climates. The humidity of typical indoor spaces is generally ideal for growing a cactus indoors. Consider that some tropical cactus species, such as the Christmas cactus, prefer humid conditions.
Repotting
Generally, cacti only require repotting once every 2 to 3 years. Choose a terracotta or clay pot with good drainage. Take care when handling cacti—wear gloves to protect against spines.
