rofl. anyone who says pot plants don't grow roots when the lights are on is just spouting crap they have read and have no idea if it's true or not. The reality is that marijuana is part of a category of plants that DO NOT NEED DARK! This is well documented, and isn't really something still open to debate, biologists have known it for longer than you've been alive
Most of these people simply can't keep up with plants that grow this fast, because they really don't understand what they are doing, they just do what other people tell them is the "best". As a result, their plants suck and they blame the light.
A properly cared for marijuana plant (meaning all bottlenecks are taken care of) under 24/0 will not only grow above ground faster, but will also grow faster below ground than any other light schedule, that's simply how this plant works
edit: This is probably the best thread I've seen explain it, no need to reinvent wheels
https://www.rollitup.org/general-marijuana-growing/292985-24-0-vs-18-6-a-3.html#post3666786
I wish I could give LT1RX7 Drifter negative rep