Something i did?

I started my plants about 8 weeks ago and they are all different strains and they were all newbe friendly seeds. Can someone tell me why three of the plants are beautiful and the other 3 are dwarfs. They are growing but for 6 weeks of veg. and into the first week of flower I feel they should have done or should be doing a lot more.

Different phenos. Wrong seeds. Are they autos? Ruderalis genes love to exhibit.