Water sparingly during the growing season, allowing the soil to dry out completely between waterings. Reduce watering significantly in winter, providing only enough to prevent severe shriveling.

Overwatering is a primary cause of root rot for Mammillaria plumosa.

Pruning is generally not required for Mammillaria plumosa as it grows as a clumping cactus. If individual stems or offsets become damaged or diseased, they can be carefully removed with a sterile knife.

This helps maintain the plant's aesthetic and prevent disease spread.

Mammillaria plumosa is easily propagated by offsets (pups) that form at the base of the plant. Gently twist or cut off an offset with a sharp, sterile knife, allow the cut surface to callous over for a few days, and then plant in well-draining cactus soil.

Repot every 2-3 years or when the pot becomes crowded, preferably in the spring. Use a well-draining cactus or succulent mix.

Choose a pot that is only slightly larger than the current root ball and ensure it has drainage holes to prevent waterlogging.