How many cosmos seeds per hole?

Could you please elaborate on the quantity of cosmos seeds that should be planted in each hole? The paragraph I've read seems to mention something about the seeding process, but the specifics are somewhat unclear. Is there a recommended ratio or does it depend on various factors like soil fertility, climate conditions, or the variety of cosmos being planted? I'm quite interested in this aspect as I'm planning to start a small garden with cosmos flowers. Your expertise in this matter would be greatly appreciated.