Strechy small Buds

Hey Everyone This is my first time growing and the bottom 1/3 of the branches have very small buds and My plant has about three in some places four inches between internodes. How can I fix this
Strain:2x Master Kush, 1x Pre 98 bubba 1x Black berry(they are all about 20" tall and 1' wide)
Footprint:4'x2.5'
Light: 400Watt Hps In air cooled Hood about (6-8 inches away from tops of plants)
Vent: 4 inch 110CFM inline fan
Pot: 1gal Maybe Two Gal Unsure!
Medium:Fox Farm Ocean Forest
Nutes: Grow Big, Big Bloom, Tiger Bloom, Open Sesame, Beastie Bloomz, Cha Ching Every other watering I feed(once a week)PH is 6.3-6.5
Room Temp:76-78 Deg

I heard that you have to cut off the bottom 1/3 of the plant but i didnt want to do it before I heard it from someone who knows what there are talking about. and If it is supposed to be done is it the bottom 1/3 of the entire plant or the bottom 1/3 of each branch.
Please comment

trim off the bottom 1/3 of branches. it gives a better main cola and more air under the plant.

Pics would be good. I wouldn't bother lolipoping them if they are close to being done.
If the main colas are doing good, don't worry about the fluffy little buds, let them be.. If you want the little fluffy buds to be bigger, you need more light.. Some people like to supplement with CFL's, just stick a few CFL's down there and let it go

increase reflective index of your walls.

its all cuased by lack of light penatration, so get more lights, and get as close to mirroring your walls as u can.

a 4 foot florescent grow bulbs down your walls would help

so it is the lack of light, well i have milar on my wall of the grow cab and milar is something like 98% reflective so i dont think it is going to get any better than that
I have three u-bend florescents can i use that instead of cfls
thanks for your input