not stretch, grow vertical. I call it the vertical stretch because its that "stretch" of time where veg mode is going ape shit. Once you have a trained eye, you'll see it. Now, that doesn't necessarily mean that they will stop growing bushy, because they wont. They continue to get fat and bushy, but the vertical stretch i refer too is when you can see all of your brand new colas starting to reach for the sky. thats when you pound em.
I'm at 1200PPM now.