How to Fertilize Wright's Easter lily cactus?
Very weak cactus fertilizer monthly during warm active growth

Wright's Easter lily cactus · Echinopsis backebergii subsp. wrightiana
Grow under glass in a loam-based potting compost with added extra grit. Water moderately when in growth, sparingly when dormant. Apply a balanced liquid fertiliser 2 or 3 times in the growing season
Very weak cactus fertilizer monthly during warm active growth