When should I start LST?

It's a guess to some extent.. roots need to be robust enough to hold. An anchor in opposite direction of where you bend plant can help a lot. If you did it now, only a couple auxiliary growths would benefit. Give it some time to grow out a tad. You'll likley diminish the lowest two growths, if they are below the bend later on. the plant reacats in predictable and localized ways. If you take a node and cover it from light.. keep it moist... it will grow roots. you can do clones this way. not a joke. The concepts of training.. understand dominance and how to break it or gain it... tallest branch, for the most pert, will dominate. The amount of vascular tissue (thickness of stems and such) is the other part. Over time, the plant heavily favors the highest growth. So, you are going to manipulate this in any way you see fit... Bend it down between 90-degree alternating growth. this allowes both sides easy access to vertical growth and less likely to prune some useless growth. Be gentle, but you'll find it is surprisingly robust. Bend in a few places.. it doesn't have to be a 90-degree bend, but you are trying to get to horizontal. At this poinrt all the stems and such will be thickening up at an even rate, if you level this off.. any node below, you might as well lop off now.. you could tie them up and make them tallest for next 2-3 weeks, if you want, too. If a terminal bud is taller than the rest, just gently bend it down or if drastically taller, tie it down, even if temporarily. If you keep everything roughly the same height, you'll have even growth. prune as well.. where you need a greater density of colas or maybe to slow something down. don't do this late as it will only diminish yield (not speaking of lollipop. don't prune for "2" shoots, if it won't grow out in time). This will cause a redistribution of resources in the plant -- mostly to the axilary buds below on that shoot. all depends on space you want to fill.. Plus an autoflower... i'd expect ~5 weeks of growth, maybe? let the top grow north in time to catch up.

When you hit your 5th node is when I suggest doing training of any sort. You want a good root system to help her deal with all that stress. Happy Growing!👊