Yes, but I was under the impression that the point of it was to keep a shorter and/or more manageable plant with less popcorn buds. Plus when you top or FIM, you're cutting off growth and the plant does take some time to recover. I do not understand why topping/FIM'ing is beneficial for such a short and time restricted plant.
All growers crave a heavy harvest. We want large, thick, sticky coronas and a plant packed with more large, sticky buds.
In states that allow marijuana growth or use for medicinal or recreational use, there is still typically a limit on the amount of plants a person is allowed to grow. We always want to get a maximum harvest, so techniques like topping have been developed to allow growers to really pull in a heavy harvest with a minimum number of plants.
Topping is also cost-effective, because you can have a smaller hydroponic system and purchase fewer clones or seeds. Here's how it works, in a nutshell.
Topping: The Basic Concept
Topping is actually a very simple process with a simple concept. When you cut your main stalk right above a node (see illustration below), two slightly-smaller main stalks will sprout from the remains. Each of these stalks will grow its own corona/cola (i.e. the big ol' bud at the top) and you will end up with a larger final haul.
Another effect of topping is that it tends to keep plants shorter and bushier, so that they can mature fully without getting too close to your lights and risking heat damage. As long as you provide adequate light (to avoid "stretch" -- the term for when your plants grow excessively tall in an attempt to reach the light) you should get two (or more) excellent coronas from a properly-tended plant.
While it is very simple, it must be done with care. Cut
only the stalk, and use a very sharp tool, like a fresh razor-blaze or specialized scissors. Some growers with sharp nails will pinch off the growth as well, which seems to be a good method also.
Choosing Topping Locations
Generally, one would let their plants get slightly larger than these ones before beginning to top, perhaps three or four good nodes worth of growth at least, but for the sake of clarity (so you can actually see the nodes clearly), we are using a smaller plant.
Topping Multiple Times
Alternative Methods
Some growers have developed their own topping techniques, from very delicately removing only the top growth from side stems while other like to be more aggressive and remove center stalks. This is just a basic guide to give you the general idea of why topping exists and where to cut or pinch off the upper growth.
As you start to experiment with your own plants, you will likely develop a topping technique that works well for you. As long as you top your plants with care and take care of them properly, this method can be used really effectively to maximize your harvest and achieve bushy, loaded plants.