deeunit1answered grow question 4 years ago Iv done it a number of times for one reason or another "days of harvesting" and the only time Iv noticed the difference is when a plant got left for over a week and left to dry out completely.2-3 days and Iv never noticed the difference.They've got the newer finishing bulbs now,they have deeper reds with UV but I'm in the process of getting a couple of cheap UV lights Ā£20 each.It increases mostly THC.