It is often assumed that Mammillaria plumosa is soft, given its feathery appearance. However, the spines are very sharp, and extreme caution should be taken when handling.Water regularly in summer, and reduce - but do not cease - watering in winter. The feather cactus is especially prone to root rot, and should never be allowed to remain in standing water. Additionally, overwatered plants are susceptible to attack by mealybugs and fungal infections. Always allow soil to fully dry before continuing irrigation, and try to prevent getting the spines wet to encourage the best growth.
Indoors, plant the feather cactus in a high-quality cactus or succulent soil. If growing outdoors, add gravel or sand to the soil to provide drainage. Good drainage is absolutely essential to prevent root rot, but otherwise, this cacti can be cultivated in most conditions and is not sensitive to pH.
Mammillaria plumosa requires bright sun. Although partial shade may be necessary in the afternoon, excessive shade will prevent spine growth and reduce the bluish color of stems. However, take care not to introduce indoor cacti to direct sunlight immediately, as acclimation is needed to prevent sunburn. The species is also moderately frost tolerant, accepting temperatures down to 20°F, USDA hardiness zones 9a to 11.
Propagation is possible by offsets or seed. While it can take many years for cacti to develop roots, cuttings grow roots quickly. For seed, harvest from fruit and sow indoors during early spring.
