i hear people topping or fimming & when they explain it they say to take so much off..i just topped my month old plant & i just pinched the new growth off the top, about half a centimeter if that....i hope i did it right
When I fim I try and shoot for 80% of the new growth. Look at the new growth where it's like a cone cut about 2/3 of new growth if done right 2 tops will emerge from the cut and the 2 or 3 side branches will grow to the same height. Topping you can chop as low or as much of the plant as you want as long as you leave a couple branches to become tops