Slow growth, growing up but not bushy

Well, you don't indicate anything about the distance between the plant and the light so I'm not understanding where my growmies are coming up with their advice about it... What I've found to be the answer to slow growth at this stage (or at ANY stage, really) is the VPD.... google VPD charts and see what the ideal temp/humidity range should be for the age of your plants... The first time I stumbled upon this advice and used it, my plants just took off - it's as if they were saying "well, thank GOD you figured THAT one out, stupido!" .... but not seeing any information on humidity, you're going to have to be the one who figures out whether this is an issue or not. You're also getting to the point in the grow where you might want to introduce a low dose of nutrients... if these are autoflowers, start them off with 1/4 strength... if they're photoperiods, start them off with 1/2 strength... Good luck! - oh, and have some patience! They're actually looking pretty good and their height is concurring with me... but I'll bet the VPD will help a lot!