Any 1 grown tutankhamun need advice

Hi all

I'm new to the site but have grown before .
I'm trying a strain of tutankhamun they are 3 weeks from seed and they seem to be stretching quite a lot. This is my first time growing in a small area .so heres what I have ..

Alien 2.4 x 1.2 x 2 (meters)
2 x 600 hps lights
1x 125w cfl
8'' rhino intake
8" rhino extractor

They are growing in coco
6 x tutankhamun
1x critical kush
1x unknown


I'm only using a 1x 600 hps while they are in this stage of there life but I do have a plant in there already which is in flower . So I was wondering how I could keep them smaller until they have thicker stems as I don't want them to get to tall and fall over I understand that this strain is sativa dominant.

Hey how are you? I would suggest replanting them up to the underside of your first set of leaves, then get them on a riser closer to the light or better yet, get a cheap floresent fixture and keep the light like 2 -6 inches from them and they will grow slower and build more roots, top it as soon as you can after replanting, like a week or two depending on growth and they will root up more. Peace, be safe MD.