if they are 1.5ft now u should flower very soon, they will double in size in the first 3 weeks of flowwering... switch the lights to 12/12 and use flowering nutes high in P......... goood luck
cheers mate for that i was gonna leave 1 more week there is ten. 7 of them just over a foot half and ther is 2 that are at about a foot so i was just gonna let them have a few more day wat you think cheers