Height problem (greenhouse)

So I have a 6x8x7 high greenhouse. I started fem seeds June 1 and I am using pure organic fert in pro mix. My plants are now almost 7 feet tall with no room left to grow any ideas on how to fix my height problem. I cut the tops off in mid June.

bend em down

I experienced the same problem,what i did was tie themn down so the could still grow but not dyeing

That's what I was thinking. I was not sure if this would stress the plants this far into veg.
I have never had plants grow so big and so fast. They all are different strains so it is not the seeds.