Has this happened to you? Very little Trichromes

On my last grow, I grew clones from a very good mother plant using a 400w MH. They grew lots of bud but hardly any trichromes. The end result was about 6oz. of dried worthless bud. I then started a new grow from seed,using seed from two different strains. This time under a 600w HPS, half my grow is producing some very nice bud, and once again, there are some from both strains that are producing nice bud with very little trichromes. They all are nearing harvest. Can anyone give a rational explanation?

What is the strain you are growing? How long did you flower them? if they are sativa dominant strain it takes at least 10 to 12 weeks to fully mature. What are your lights.

What is your feeding regimen like..kind of nutrients?

The first grow was OG Kush. I used GH 3 part for nutrients. This current grow is Hogs Breath and some Sativa from Mexico. I am using AN Sensei Bloom. I feed them once a week and need to water every other day. The Sativa is in it's 10th week of bloom, half are doing great with plenty of trichromes and aroma, the other half of the Sativas just have bud with none to very little trichromes on it. The Hogs Breath is in it's ninth week of bloom and just has bud and no aroma or Trichromes. Both strains are currently under a 600w HPS.