Growing Lowryder Plants

I am growing a couple different plants, but I want to focus on my lowryder plants. Here is my plant at day 18. Any comments on how you think its doing? I am a first time grower. Any advice or suggestions will help. Here are pics of my *AK47 x Lowryder 2* plants. I am growing with Fox Farm ocean forest and am using GROW BIG Fox Farm Nutrient for veg stage and TIGER BLOOM once they begin flowering.

my plants seemed to stay rather short also. i am at day 21 and, while there are lots of leaves, not much vertical growth at all. any ideas about this?