Why are my plants so short?

[TryingToDo]

Hi guys,
I have 5 random bag seeds.
As seen from their appearances they are all different.
I have started flowering (12-12) 3 days ago in their 6th week.
They are all short although they all look happy.
I use biobizz light mix-all mix mixed soil with fabric pots 3 of them in 5 galloons and 2 of them in 3 galloons.
I gave em 1ml bio grow per 1 lt with rhizotonic.
Now ı give em 1 ml bio grow with 1 ml bio bloom.
They will stay undet my 400w MH.
Looking for ur answers desperately

 

[NewMexicannabisFarmer]

Your plants are doing great don't stress, I have notice plants stretch less when night temps are above 70. Not sure what you climate is like, but a healthy plant is a healthy plant. I have grown mendo breath in a fat garden bed outside and it only grew like 2 feet tall and wide, but made some amazing flowers. Darn plants must have been 6 months old when harvest rolled around mid October

 

[NewMexicannabisFarmer]

Also they were possibly switched to flower too early.