Late in the vegetative cycle of marijuana, as the tallest branches begin to excel upward they can get too close to the light as well as block light from getting to the lower parts of the plant. Using “Low Stress Training” (LST), is one way to safely encourage more vertical growth and help keep the canopy & light coverage even.
The biology behind this is that the highest plant tips contain a hormone that triggers lateral growth into becoming the top when it (the original top) is removed (damage, topping, fimming, etc.), so rather than remove any growth to achieve this, or having to break or snap branches in the case of “supper cropping” LST is done with simple bending & tying (hence low stress).
As mentioned previous, in addition to the hormone triggered growth, if a plant is receiving an uneven amount of light inner & lower growth can suffer due to low light. With LST you essentially spread the plant out horizontally, throughout available space, spreading the light evenly over the whole plant.
Some strains take better to LST than others. Some bushy Indica phenotypes need little encouragement as their lowest branches often will grow as tall at the top itself, naturally. Certain Northern Light phenotypes and some hybrids like Jack Herer (pictured above), do exceptionally well with a little LST.
The Haze Auto (on the left) needed virtually no training as her lowest branches grew as tall as her top, I did utilize some training merely to open her up and allow better light penetration.
I truly believe that low stress training properly done will usually improve yields. In the worst case it will surely improve the overall quality of the harvest.
Let me know your thoughts!