Hi
@BigStretch! Plants are like us, they need to rest. Dark phases help plants to recover from stress, but this is also the time for vertical growth. Growing regular strains I like to give them 18 hours of light, sometimes less is more, plus you will make some savings on the energy. It's a personal opinion, each grower has its preference. Hope this makes sense, let me know in the comments section if you need any further information, and happy growing! 👊