The Notocactus leninghausii, often recognized as the Golden Ball Cactus or Lemon Ball Cactus, is a favored succulent for both novice and experienced plant enthusiasts. Its distinctive appearance includes a globular shape that can become columnar with age, bright green stems, and soft, golden, bristly spines. This plant also produces vibrant, silky yellow flowers, typically blooming in spring and early summer once mature. Its relatively straightforward care contributes to its widespread popularity.
Essential Care Requirements
Light
The Golden Ball Cactus thrives in ample bright sunlight. Full sun exposure is generally beneficial, but intense, direct afternoon sun, especially during the hottest parts of the day, can lead to scorching. Morning sun is often ideal as it provides strong light without the extreme heat of midday or afternoon. Insufficient light can cause the cactus to stretch and become pale, weakening the plant and inhibiting flowering.
Watering
Proper watering for Notocactus leninghausii involves a “soak and dry” method, allowing the soil to dry out completely between waterings. Overwatering poses a significant risk, leading to root rot. During the active growing season in spring and summer, water regularly, ensuring the pot drains thoroughly. In the dormant winter months, significantly reduce watering frequency, keeping the soil nearly entirely dry.
Soil
A well-draining, gritty, and fast-drying soil mix is paramount for the Golden Ball Cactus. A specialized cactus or succulent potting mix is recommended, as it allows excess water to flow freely and prevents waterlogging. Enhancing this mix with inorganic components like pumice, perlite, or coarse sand further improves drainage and aeration. Ideal compositions include a blend of fertile loam, pumice, and coarse sand.
Temperature and Humidity
Notocactus leninghausii prefers warm temperatures during its active growing season, ideally 20°C to 30°C (68°F to 86°F). To encourage flowering, cooler temperatures between 10°C and 15°C (50°F to 59°F) are beneficial during winter dormancy. While the cactus can tolerate brief periods of mild frost, it is not frost tolerant and should be protected from freezing temperatures. This species is well-suited to dry air, so humidity is generally not a concern.
Potting and Repotting
Selecting an appropriate pot with drainage holes is important for the Golden Ball Cactus to prevent water accumulation and root rot. When the plant becomes root-bound, typically every two to three years, or when the soil needs refreshing, repotting is advisable.
Repot carefully, ideally at the beginning of the growing season. Gently remove the cactus from its old pot, using gloves or folded newspaper to protect your hands from its spines. After removing excess soil from the roots, place the plant into a new pot that is only slightly larger, perhaps 2 cm wider than the previous one, and fill around the roots with fresh, well-draining cactus mix. Do not water the plant immediately after repotting; instead, allow any minor root damage to heal for a few days before the first watering.
Common Problems and Solutions
Overwatering is the leading cause of root rot in Notocactus leninghausii. Symptoms include a mushy base, discoloration (yellowing or browning), and a foul odor emanating from the soil. If root rot is suspected, remove the plant from its pot, trim away soft, dark, or foul-smelling roots with sterilized shears, and allow healthy roots to air dry for a day or two before repotting in fresh, dry soil.
This cactus can be affected by common pests such as mealybugs and spider mites. Mealybugs appear as white, cottony masses, while spider mites might cause fine webbing or tiny discolored spots on the plant surface. For minor infestations, these pests can be removed manually with a cotton swab dipped in rubbing alcohol, or by using insecticidal soap.
A lack of flowering in mature Notocactus leninghausii often stems from insufficient light or the absence of a proper winter dormancy period. To encourage blooms, ensure the plant receives adequate bright light, especially morning sun, and experiences cooler, dry conditions during winter. Plants that are consistently turned towards the sun may also be inhibited from flowering.
Etiolation, or stretching, indicates that the plant is not receiving enough light. This condition results in pale, elongated, and weakened growth as the cactus stretches in search of more light. While existing etiolated growth will not revert to its compact form, moving the plant to a brighter location will ensure that new growth develops normally.