Combine 3 parts coarse sand, 1 part coir, and 1 part perlite to create a soil mixture suited to the needs of crested golden barrel cacti.
Drizzle water over the soil mixture while mixing it by hand. Keep adding water until the mixture feels moderately moist, but not soggy.
Fill a 2-inch-deep seed tray with the moistened soil mixture. Leave a half-inch space between the soil and the top of the tray. Press the soil into the tray to even the surface.
Sow the crested golden barrel cactus seeds 1 inch apart and 1/16 inch deep. Press the seeds into the soil, then sprinkle a thin layer of sand over them.
Set the seed tray on a coil propagation mat set to 75 F under a source of natural or artificial light. Expose the seeds to bright light for six to eight hours a day.
Mist the crested golden barrel cactus seeds whenever the top inch of soil completely dries out. Use a spray bottle with a mist setting, or use a standard pump-action plant mister.
Watch for germination in 14 to 21 days. Keep the seed tray on the coil propagation mat until the cacti begin to flesh out and develop a rounded shape.
Transplant the crested golden barrel cactus seedlings into individual 6-inch plastic pots filled with the same soil mixture once they begin to turn green.
Keep the crested golden barrel cacti under high, light shade for two weeks. Gradually acclimate them to strong light by exposing them to direct sunlight for short periods of time over the course of several weeks.
Plant the crested golden barrel cacti in a permanent bed with sand- or gravel-based soil approximately one month after transplanting them into individual pots.