Green crack is NOT an indica strain, its a sativa dominant hybrid. Been growing the lady for awhile now. I've had the same pheon through taking clones now for a year and a half.
Green crack is a rather odd sativa dom though, it usually flowers in 8-9 weeks depending if you want amber or cloudy trichomes and won't give you giant colas, but you'll get a nice yield of smaller nugs. It turns out to be abeast of a bush too.
This one here was vegged inside under a 400 watt hps for 10 weeks, transplanted into a 20 gal rubbermaid and thrown outside for flower.
edit* for some reason it put 2 of the pics up sideways sorry about that.
Your plants are looking good, and you'll definitely get some good smoke, keep us updated on when you harvest