Fastbuds Blackberry

Well she's growing like crazy, I'm worried she's going to outgrow my tent if she doesn't stop stretching. Light is at full strength now and only 13" away from top of the plant. Leaves are yellowing at the bottom already which seems too soon to me so I will be bumping up the nutrients to see if that changes at all. If not then I'll just let her do her thing. She looks like she's going to fill in nicely and I'm starting to see some purple hues showing up in the buds. She's definitely fully in flower and should start stacking up.