Speed up growth??

“Doctor, I have two twin children but they’re not identical. One is taller than the other. What can I do to make the shorter child catch up in height?” Sounds a little silly when phrased in human terms, eh? But we can control height of plants somewhat, as you’ve been advised already by @MangoDudu. But I’d keep feeding food/nutes. Don’t hold back a plant that is thriving. If runt doesn’t catch up, so be it. Now you know why I germinate 60 seeds at a time, put 24 of them in soil, and end up growing only a few to harvest. But that’s prohibitively expensive for a typical grower, and a great reason to grow regular photoperiods, and breed to have stock of your own seeds! I have thousands I keep in airtight jars, wrapped in foil in the fridge. Lots of people scrog, but it seems like extra work to me. If you like spending that much time tinkering in the garden, enjoy! A gentle breeze to make leaves dance a slow hula is all they need to grow strong and never require support. On rare occasions I’ve had to wrap a bungee around plant to hold up branches late in flower. Simple and easy and about 10 seconds of effort. Keep at it! Enjoy the process as much as your harvest!