@Dendegrow, under the top growth, while they are still in veg, so it thickens & strengthens the new growing stem. Or early on in flower after the flowering stretch if they have really stretched a lot & have week stems! If the stems do bend over, pinch them at the bend & they will grow a thick type of knuckle & strengthen the stems above it. This is from my personal experience but going off things I've read about H.S.T. training & some thing that's been proven from other growers.
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