I'm pretty sure its the soil, this same experience happened to me, get some quality soil sir I use fox farm happy frog, next time get some cups that aren't translucent. Keep us updated.. These guys are messing with u lol, I want to help out, I'm on my 3rd grow and I think I am averaging about 1.5-2.5 oz per plant. Give us your entire setup (i.e. light source,watts, soil, doesn't look like u are using any fertilizer yet,).
I don't know if this was a joke or not...
But 3 weeks of veg, and 60 days of flower (on average) you should have harvested by now.
This happened to me, knowledge is key.