man your growing in soda bottles, you won't get big plants like this, and is that soil in half a bottle put into another half with water? your trying to hydro?
if you wanted big buds, get big pots or try hydro like DWC, just grow one plant, and you'll yield more than all the plants your growing now combined, am doing that now its amazing how fast it grows, these pics when it was 2 weeks into bud 12\12, check photo
1 lady under 400w hps topped many times and now LST, i know i'll get 4 to 5 ounces minimum out of it ,
my last plant was half this plant and got me 3ounces
in your case get some nutes it will help, get something with more on the P and k, and an HID light makes all the deference
420