To get small, compact plants, here a few things you can do to help.

First off, to keep a small plant, you want an indica dom. strain. Avoid sativas as they like to grow tall and lanky. Indicas stay short and thick.

You said you are using floros, so you can get as close as an inch with those bulbs as they give off very little heat. So keep your lights close to your plants, as that will reduce stretching.

Keep your grow area coolish. Overheating in a grow room will result in stretched out plants. Try and keep it above 15degC, and below 30degC, and you should be fine.

And yes, how many watts are your floros as Sirus asked? If it is too low of wattage, your plant will stretch as it requires more light. Plants will stretch if not enough light is provided. To get anything decent, you want a min of 50W per.sq.ft.

Good luck...