First time grower needs some asstintce, pleaseeeeee

Ok here is my problem I vegged 11 plants under a 400 watt MH and i have grown them too big , alot of the bottom branches are tvery weak and are not getting much light, is it worth getting a 600 watt hps to flower them . The space i am growing in 6 foot long by 3 foot wide. Pleaseeeee reply

a 600 watt light will have better canopy penetration helping your lower branches, but it's not at all unusual to have the lower branches be significantly weaker than the upper ones. look up training techniques like LST, topping, fimming, super cropping - all are ways to manage the size and shape of a plant to maximize yield in a minimum of space.