Sorry, but I'm finding it hard to get the question. You are growing outside. So why would you want to keep it low?
Anyways, I don't get the question.
But to keep it low. You can top. And supercrop. Feel free to DM me in more details about these. (I really don't feel the need to explain) cause tbh you are growing outside
You can do some lollipoppimg to get a better bud quality at the top but even that I wouldn't do. You are growing outside bro.
Outside grows tend to be at least 1/3 to 1/2 bigger than you would grow inside because of the sunrise and sunset and the movement of the sun makes your plant grow tall.
If you explain to us, y, as I'd love to know y you would want to keep an outdoor grow short. Sorry, I just don't get it??