yes it is true... your plantswont grow untill u shut off the light... so if u do 24/0 for how ever u wont see a MAJOR defference untill u shut off light .... like with sativa's the trick is too shut off lights for 3 days.... THEY WILL GROW..... like 1 -2 feet.... your plants needs to rest it's alive... so think off it how would u feel if u were up 24/7 wid no sleep u wouldnt function right... well plants r the same...