Slow growing

Hey all, I am kind of new to growing but since I am growing outdoors I figured I would post here. I have 3 plants and have treated them the exact same throughout all of their lives. But for some reason one of my plants is growing fine and the other two are stunted. I got the seeds off a friend so they may just be low quality(dont know the strain).

I have been doing everything suggested on the guides I have read but most of them seem to concern indoor growing.

Is there some trick that I am missing or do I just wait for the grass to grow? BTW I am in Florida.

maybe one is getting more sunlight than the other? I have a couple plants like that outside my self and at certain parts of the day that plant gets more sun that the others. And that plant is doing better than the others but there all around healthy are the other ones dying