Echinocactus grusonii inermis

Botanical Name — Echinocactus grusonii inermis

Common Name — golden barrel cactus, mother in-law’s cushion

Plant Family — Cactaceae

Background

Known for its globular shape, and striking golden colored spines the golden barrel cactus is a popular specimen for home gardens and botanic gardens alike. In its wild habitat of central Mexico however, it is rare and endangered. Where it is endemic it grows in high altitudes on volcanic rock slopes. It is quick growing at first, with its growth rate slowing as it matures. It can take 10 years to reach 10 inches in diameter and is capable of ultimately reaching one meter in height. The inermis variety produces shorter spines than the species plant.

Growth Requirements

Sun

•  Golden barrel cacti prefer plenty of sun. At least five hours of direct sun is ideal. 
• If growing this plant outdoors, place it in an area where it will get light shade to protect it from intense, mid-day sun.

Temperature/ Humidity 

• This desert plant prefers warm temperatures. Ideal conditions range between 50 and 75 ºF. If grown outdoors, bring this plant inside when temperatures fall consistently below 40 ºF.

Water

• Echinocactus are extremely drought-tolerant. Water thoroughly, fully saturating the soil. Allow soil to dry out entirely in-between waterings. 
• In the summer water plants consistently. Water much less frequently during the winter, cutting down to once every one to two months.

Soil/Roots

• These plants prefer a gritty, well-draining mix. A cactus or succulent soil would work great. You can amend a soil mixture with sand or fine pumice up to 50% to improve grittiness and drainage. 

Flowering

• Golden barrel cacti will produce yellow flowers from the crown of the plant, typically during mid-summer, though these plants rarely flower indoors. Golden barrel plants are typically grown for their foliage rather than their flowers.

Fertilization

• Golden barrel cacti do not typically need fertilization. Fertilizer can be added to replenish tired soil or give your plants a boost during the growing season. Feed once a month using a high potassium fertilizer or one formulated for cacti and succulents. Fertilize only during the growing season, spring through summer. 

Propagation

• Propagation by seed is the most reliable way to propagate this plant. Sow freshly harvested seeds in well-drained, moisture-retentive soil. Keep soil consistently moist, and provide ample humidity to encourage germination.

Health

Diseases

• Golden barrel cacti are hardy and not especially prone to pests or diseases. Bacterial and fungal infections are uncommon and typically result from overwatering and excessive humidity. Always err on the side of underwatering and place your plant in a spot that gets good air circulation. 
• Keep an eye out for aphids, spider mites, and mealybugs. 

Maintenance (pruning, legginess, repotting)

• Younger plants are fast-growing and should be repotted about once a year. Once your cactus is a few years old and starting to mature, growth will slow down. At this point, you can repot less often, about once every two to three years.

Toxicity

• Echinocactus grusonii is not known to be toxic to pets and humans. Still, it possesses very sharp spines which can cause injury. Keep out of reach of pets and small children and take care when handling these plants.