How can I manage a tall lanky sativa indoors?

Contributed by Oldtimer1:

Firstly you do need enough height. If you have that they will need supporting and the best way is with a device we call a yo-yo. This is a spring loaded reel with about 2 meters of line in it. It has a plastic hook on the end. The Yo-Yo's one for each tall type plant is hung at the top of the grow room and the hook on the line is pulled down and hooked around the plant stem as soon as it starts getting tall enough to be floppy. As the plant grows it is wound around the line and the spring tension keeps the plant grows upright and straight.