I know you can top them but how do you guys keep them so short and they still produce a good amount? Im in a closet with cfls and i average 1 to 2 ounces per plant but it is killer.
The best way I think to keep your plant small is after a few weeks of veg. Trim close to 50 percent of the leaves off but if you do more than that you might kill your girl. But trim both sides top and bottom to make sure your plant is still pretty even. Then your plant will only focus on growing new branches to replace the ones you cut and new ones will form too. By doing this you can keep your plant only a few nodes high but very bushy. After you cut up your plant wait about two more weeks of veg and repeat if need.
Use small pots, pick a small strain like a full indica strain, maybe try an autoflower (Joint Doctor, Short stuff seeds), keep lights very close, train a lot (LST + topping). Maybe put a scrog screen in there and keep pushing the branches to the outer sides whenever they pop up through a hole, just keep pushing them under and out further. You can induce flower quicker (12/12 while its at like 5-7" or something). You can even do 12/12 from seed/sprout. Thats about all I got, but you can check this out too.