Do you have a fan blowing directly on them so their stems will grow strong? A strong stem supports big buds. That height they should be waving at you, which also keeps them cool but you are using LED.
How about describing more the LED? Specs? Company? Soil looks dry. Big organic movement happening. All the work is done in the beginning and all the nutes are IN the soil. Never have to feed your plants ever, just water. I don't think LEDs are THERE yet, to be honest. Another year and they should have a few rock solid systems out there. It'll be the new thing, everybody will want one. For now, should just get an HPS/MH light system off ebay for $120 or something similar. Even a handful of CFLs would be good. Like 5, 85 watts a piece if not 100 watts each.