deFharoanswered grow question 6y ago There's really nothing that proves the plant improves with 24-48 hours of darkness before harvest; all there are are subjective impressions. Harvest the plants when the daylight period ends, make sure the pot has very little water, and if you can, follow the phases of the moonâcut from 3 days after the waxing moon until 3 days after the full moon, avoiding harvesting on the full moon. Cheers.