No Trichones & Crystals??!!

So, after many trial and errors (6 plants to be exact), I finally managed to harvest 2 plants out of 3 grows. My first and second grow i harvested around 20 ounces of shit herb which had no crystals whatsoever therefore i threw all this away. My third grow i just cut down the plants now and harvested around 2 ounces from 2 plants, which were full of crystals.

I grew in the same manner, gave the same nutrients, my question is - what can make a plant not produce any trics??

The only difference in the grows was that the first 2 grows i left the plants get pretty big before putting them into flowering. My last grow the plants were quite small but full of trics - so what can make a plant not produce trics??
I add that they were all different strains.

high humidity, poor genetics, poor lighting and maybe they were males. just a few possible reasons.

the genetics was a possiblility if the seeds were from one shop but they where from diffrent shops so it loweres the possiblity humidity was good i have 600W lights and they where all female i eliminated one hermi

so no body has and ans for this

Heat plays a big factor, if you're not controlling the temps properly they will stress out.

Maybe they needed to flower longer

Size of the plant isn't your problem.
Nutrients arent your problem, unless you're burning the shit out of your plants. If they look decent and green, this probably isn't the case.

It could be a combination of poor genetics and environmental factors. Do you have adequate air exchange? what's the temp/humidity of your grow room? Figure out these issues and your problem might be solved.

Pics help.

I had good circulation and everything was correct still not sure wat went wrong i am growing some blue cheese not gonna leave them grow much to keep them small i use advance nutes all i need to buy is some micro nutes hope all goes well not gonna give up so easy haha

Temp of my grow room was 29 and 52 humid which was good

If your setup is right then it has to be a personal error somewhere along the line, not to put you down though bro. Do you have a truncheon and what were you doing with the ph. I have only had I harvest but my plants were 6ft covered in tri's dense and sticky. I don't believe the size can affect the amount of trichomes you get as long as light penetration is good and you are giving it the right things at the right time

I have 2 6footers, 4weeks into bloom. One looks like it has been frosted, the other I have to search to find any trics. Same grow, same environment. The only difference is they are of different genetics. I am guessing the one without many trics is just going to take longer to finish.

so how long could u leave in flowering? i had 4 footer but there where no trics and all hairs red s her down i have pics of them if u wanna see them

What strains are you growing and did you grow from seed

add a UV bulb, its probably just a longer flowering strain. dont fret over it, just get better genetics or clone them frosty ones ya got there!