To 1: Preflowering usually begins in the 4th week of vegetation. Preflowering can only be detected by magnification. At the 4th node down the stem, you should be able to see the tiny pear - shaped node which identifies the female, along with the two tiny pistils. Make certain you see in your magnifiers the hairy-like white tenticles.
Full flowering begins 1 to 2 weeks after changing the light schedule to 12/12. In a matter of days, most or all of the nodes on the marijuana plant will be covered in white pistils. These will begin to develop into flowers, which will reach their maturity in 6 to 8 weeks` time.
To 2: Expect your plants to grow twice its original size at the start of the 12/12 cycle. In order to control that, go to Home depot, get a trellis netting (in the garden section, 4 bucks), make a frame out of 1x2 and staple the netting to the frame , then hang the contraption from the ceiling lowering in onto the plants, forcing them to grow sideways. No need to do any hairsplitting maneuvers with your plants. This way you also have a sort of uniform height of a alll the plants. You can make one big frame or several smaller ones. As the plants grow you can pull the frame slowly up. Be gentle.
to 4: don't cut off the big fan leaves.
Typically what I do is tuck them out of the way. If they are really in the way then I take the leaf and cut half of the tips off (cut at the knuckle of the leaf) this seems to be a happy medium. This technique has worked for me. Previously when I removed the entire leaf/stem I found that the the budsite at that leaf/stem node seems to lag behind. However, I "clean out" the entire lower portion, week by week a bit, of small branches and small buds in order to let the plant concentrate on the tops where you want your big buds.
to 5: Cloning from flowering plants is veeery time consuming, as it takes many weeks for that plant to return to vegetative state. Rather find out through pre-flowering (usually after 4-5 weeks in VEGETATIVE state) the sex of your plant and keep one that has shown to be female as your mother, meaning, leaving her in vegetative state forever, taking your cuttings from her. You can keep topping that plant thus controlling the size for quite some time.
happy growing!
