HELP! Why they dont grow tall enough?

[ufzsolo]

Hi y'all!

I came with two questions today to you guys, hope someone can help.
So first of all im having a bit trouble with my girls. The dont really wanna grow high, the rather bushy than tall. Ive got sativa dominant strain but they just dont grow as high as i want them. What can I do? The main problem is that they suffocate each other, i trimmed of some side branches from the bottom and a couple of fan leaves from the top hoping they get more light, but so far didnt achieve my goal.
Setup:
1.2x1.2x2m tent
1000w mars hydro led
soil with 40% perlite
AN base nutrients and Big Bud nutes
Moby Dick Auto Fem 8db
43days since germination.

Question number 2:
I would like to produce autoflowering feminised seeds as well from the same plants. I have an STS mix ready (silver nitrate and sodium tiosulphate) to spray the pistils abd budsites. My problem is i dont know when to spray them. I have pistiles and small bud sites already, so i might be late by now.

Many thanks!!!

[SoOrbudgal]

Raise the light and show a pic they stretch more when blooming

[JeffInCanada]

HI ufzsolo
The link below should help with the fem seeds. A few photos of your set up will help. How high do you have your lights? How are the temperature and humidity in your tent? I have grown Moby Dick auto before and they grew to about 65 centimeters (25 inches) tall. Autos do not typically grow very tall.

[ufzsolo]

Yeah sorry guys i forgot to take photo. Here they are.
The lamp is at the very top now, humidity is around 50% and 23-25C temp.

[JeffInCanada]

They look good to me, normal height. Looks like they just started flowering...they are going to stretch taller now.

[Ziemelblazma]

Do You leave lights on 24h/day? Maybe add some dark hours, plants stretch at night more.

[ufzsolo]

I have them on 20/4. maybe should reduce to 18/6?

[Ziemelblazma]

That might add some length

[dilvish]

Autos tend to grow smaller than photoperiods, so it may just be the strain you are growing. Aside from that they look like they may be having a nutrient problem judging by the coloration of some of the leaves. Suffocation will happen when too many plants in one space. Defoliate sparingly and make sure you have good air circulation/fans. Dropping the light cycle down likely won't help so keep it were it is now.

[ufzsolo]

What kinda nute problem did u notice? Im having hard time finding the cause of leaf discoloration. I was thinking on potassium but im not sure, what do you think?