Quote Originally Posted by Cannabis Grow Bible
Pre-flowering is a sign that your plant is mature enough to
start flowering. As a grower you have a simple choice to make. Do you
want to flower now? Or do you want to continue vegetative growth?
Here are a few facts before you make that choice.
- Some cannabis plants can be kept alive for up to 10 years by simply
keeping a light on the plant at all times. These plants will grow to a
certain height and then form into a bush. It will then eventually stop
producing branches and will spend the rest of its life growing new
leaves to replace the old ones.
- Bud production is not equal to the height of your plant. Bud
production is equal to your growing environment, your strain's genetic
make-up and the amount of nodes that the plant has. All nodes are
potential bud areas, but every strain has a genetic threshold for bud
production.
- It is possible to get more bud with lots of plants which are flowered
as soon as they are mature (which also keeps them shorter and
smaller), than extending vegetative growth with less plants until they
reach their maximum height and size. The time frame for the shorter
option may also produce more bud turnover per annum.

Keeping these things in mind, you can either choose to flower
now or choose to keep your plant growing until it reaches its size
threshold before you start flowering. If you take the longer route then
prepare to have the space for it, because when you flower most
cannabis strains they can sometimes more than double in height and
width.
If you have pre-flowers and want to flower you only have to
do one thing. You must put your plants under a 12/12 schedule.
(from the cannabible, it's downloadable)

oh yeah, and these are alternating nodes (not a weedplant)