Water thoroughly when the soil is dry, usually every 2-3 weeks during the growing season. Reduce watering significantly in winter, allowing the soil to dry out completely between waterings.

Avoid waterlogging, as this can lead to root rot. Ensure good drainage.

Pruning is generally minimal for Eulychnia castanea. Remove any dead, damaged, or diseased stems as needed.

Pruning can also be done to shape the plant or control its size, but avoid heavy pruning, which can stress the cactus. Best done in spring.

Propagation is typically done by seeds or stem cuttings. For cuttings, allow them to callus for a few days before planting in a well-draining cactus mix.

Seeds can be sown in spring in a cactus mix and kept lightly moist and warm.

Repot Eulychnia castanea every 2-3 years, or when it outgrows its container. Choose a pot with drainage holes and use a specialized cactus or succulent potting mix.

Repot in spring before the active growing season begins. Handle with care to avoid spines.