Minecraft wiki entry for Daylight_cycle, associated text: During the nighttime, the world is covered in darkness; the internal sky-light level falls to a minimum of 4, which allows hostile mobs to spawn on the surface. The exact duration for which hostile mobs are able to spawn in exposed areas is 13188 ticks.[note 1] Regardless of the low light level, crops continue to grow during the night as long as one player is not sleeping.