how long befor i top my plants

my plants are growing great only about 6 days old when can i top them so they dont grow so tall, and some advice on how to top would be nice.

Do you have any pictures so we can see where they're at right now?

I wouldn't top them, I'd tie them down (LST = low stress training)

Even if topping I would think you'd want them to get bigger so you won't stress them out so much. They're just babies right now.

check out the growfaq section on this site, i think it recommends topping after the 4th node (set of leaves).

various topping methods are in growfaq but you can simply pinch off the main growth tip with your fingers.