Just looking for some advice on why my plants are so short

[Growguy1254]

Flipped my plants to 12/12 roughly 4 weeks ago. None had pre flowers and only started showing sex 2-3 weeks ago. I have 1 big plant that I vegged for a month and trained her to be bushy. Question is my plants were around 35-45cm tall in veg and now they are like 60cm max being 70cm. They have barely stretched and its week 4 wondering if this is okay and just due to me training them. I have the following strains.

Photoperiod:
Fast amnesia
Bruce banger
Badass og cheese
The white og
Jack herer
Random clone as the mum I vegged for a month or so
Autoflower:
2x diesel
2x blue amnesia

Really not sure why the plants havent stretched as much and the white og which is indica dominant is the second tallest out of the lot. Thanks people.

 

[Growguy1254]

Autoflowers growing in coco and perlite 80% coco 20% perlite.
The rest are running in 3 month slow release fertilizer, obviously not the best but cant find organic around here and there doesnt seem to be many issues with using it over coco as of now.
Water once a week and slowed nitrogen nutrients at the end of week 1 flower and started feeding phosphorus heavy notes. Week 3 I treated with nitrogen again due to having a deficiency but that's going to be my last nitrogen feed

 

[Jimster]

Stretching varies by a number of factors. Lower light levels tend to produce taller plants, as do shorter growing hours. That is on top of the genetic predisposition to stretch, with Sativa's stretching a little more and continuing to grow a little while flowering. If you are getting flowers/buds, then it is pretty well done with stretching, except for the Sativa strains, which might stretch a little more but not greatly. Your feeding regimen sounds good... I am one for feeding a lot less than what some feed their plants. Keep up the good work!! If you start to see yellowing fan leaves, don't panic as it is fairly common. Depending on how long you plan on flowering, you might consider a very light 1/4-1/8 normal dose of fertilizer, although the timed release might be sufficient. It is usually good for about 3 or 4 months.

 

[Beachwalker]

Autoflowers growing in coco and perlite 80% coco 20% perlite.
The rest are running in 3 month slow release fertilizer, obviously not the best but cant find organic around here and there doesnt seem to be many issues with using it over coco as of now.
Water once a week and slowed nitrogen nutrients at the end of week 1 flower and started feeding phosphorus heavy notes. Week 3 I treated with nitrogen again due to having a deficiency but that's going to be my last nitrogen feed

You need to feed nitrogen the first month of flower at the very least

they're short because they're probably too crowded, might be more going on as well?

 

[Cannabizz]

They are short because you trained them. When you see the taller plants, most of the time, they haven't been trained so they grow straight up. When you top it, you stop that main branch and it forms a 'Y" shaped branch which then stop the upward growing and it turns more into a bush. It's normal. You don't want them to get too tall because you want the flowers to stay cool and not heat up from growing too close to the light in a closed space. It should be all normal and they all look good so I think you are doing fine.