Branches stems not extending (how to stimulate branch growth)

hello fellow cannabis cultivators! peace be with

I have 6 plants, 9 weeks through, all Orange Crush strain.

They are all prospering except this one is growing the inner leaves and all but their branches are not extending out. (my other plants' stems are all extending much more)

how do I stimulate them? or should I just leave it be.


-Feeding with FoxFarm GrowBig-Outdoor-Organic-

Troubled Plant:
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Healthy Plant:
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