This is the best free video on growing marijuana I've seen. It kind of reminds me of those educational videos we used to watch in school, except it's actually covering something useful.
If you're a beginner looking for a great guide, this is perfect. If you're an advanced grower, you'll probably know most of the info already, but you might still pick up a few good tips.
The video was produced by the Cannabis Training University. It's one out of something like 100 videos on growing. If you're curious about the CTU, click on that link above to visit their website.