Water thoroughly when the soil is completely dry, typically during the growing season. Reduce watering significantly in winter, allowing the soil to dry out between waterings to prevent root rot.

Ensure good drainage to avoid waterlogging, as this cactus is susceptible to overwatering.

Pruning is generally not necessary unless removing dead or damaged stems or to control size. Use a sharp, clean knife or pruning shears. Allow cuts to callus over before replanting if desired.

Pruning can also be done to improve air circulation around the plant.

Propagate Acanthocereus fosterianus from stem cuttings. Allow cuttings to dry and form a callus for several days to a week before planting in well-draining cactus mix.

Roots typically form within a few weeks when kept in warm, bright conditions.

Repot every 2-3 years or when the plant outgrows its container, preferably in spring. Use a gritty, well-draining cactus mix. Choose a pot slightly larger than the current one and ensure it has drainage holes.

Handle with care due to spines.