BB_UKanswered grow question 3y ago Gromie! It's relative really! 24hrs is the best for the best result for yield BUT raises costs on energy! 20/4 gives you again great yields more cost on energy! 18/6 is perfect for growth and saving energy, so I went and did 19/5 just to be on the inside of what's best! So what's best!? 19/5 if anything jump onto fastbuds website and they show the outcomes of the light schedules! I also did 24 hours but had my light at 8-10" at 25% in the first 2 weeks then upped to 50% at 12" for 2 weeks then upped to 75% for 2 weeks at 12" then for the remainder I turned up my light to 100% until the end! Which gave me full growth and saved money on energy