thanks a lot i will do a bit more research on thisThat depends entirely on how long you veg. Think on it this way: What you're doing is spreading the plant out, creating more than one primary shoot by tricking the plant into delivering more auxins to the secondary growth nodes. These, being level with, or higher than the main growth tip(which is bent over toward the soil). This tells the secondary nodes that they are at the top of the plant, causing them to branch like each of them are the primary shoot. The problem with this method though is that the growth nodes on the underside of the plant must be trimmed off or growth can become too tightly interwoven. This causes too much canopy interference and lower leaves get no light at all.
LST can be an extremely useful tool for certain types of growing, but I personally will not use it anymore. My new grow is light entirely from the sides, and thus will not need training. The secondary growth nodes will react to the light(and synthetic auxins from a foliar spray), and branch toward the lights.
If you can't grow with vertical lighting, or at least supplemental lighting on the lower parts of the plants, then I recommend you study a technique called FIM. This stands for "Fuck, I Missed". It was a technique probably discovered by accident. Unlike traditional topping, you don't remove the entire top growth node. You simply stunt it by removing up to 70-90% of it. In a lot of ways this is simply a more surgical version of a method called pinching, where you pinch the top growth node to stunt it. While the top node is recovering, the plant needs somewhere to dump it's resources, so it switches production to the secondary, lower nodes, which causes them to receive more auxins and trigger as primary nodes. These branch outward, and when the original main node recovers, it will form as many as 2-8 new branches where initially there as just one. How many it forms depends on many factors including the genetics of the plant and how precisely you performed your cut. This causes explosive, and symmetrical growth, rather than the off-set growth caused by bending your plant one direction or another.
Now once you have done the FIM, the numerous branches caused to become primaries will be dense and bushy. Now you can use LST to radially train the new branches away from the center of the plant, causing it to spread out even more. Once this is done, you trim off the growth on the bottom of the new branches opening up the canopy more and avoiding awkward branches that have to bend 180 degrees to grow up toward your lights from the bottom side of the branch. Do a Google Image Search on "LST" "marijuana". You'll find a lot of stuff covering this technique.
Once you have trained the new branches outward, then you can in turn FIM the end branch of each of those. With careful control, you can precisely govern the exact spacing of the vertical bud colas through careful training and trimming. Multi-approach training is the best way to go really. I've produced some amazing little bushes in the past this way. A lot of people kind of do this with their mom plants without even thinking about it or planning it real well, but it really can be done quite precisely. The combination approach makes everything so much more symmetrical. I can't stress that enough.