Vegging = vegetative stage. Its the period of growth from a seed to the flowering period. Length of time depends on your height requirements, along with the strain. Keep light on for at least 18 hours/day - Bluer spectrum bulb if possible.Flowering stage is the period when flowering begins. Use a yellow spectrum bulb, harvest when trichomes are at least a little bit amber.That's a brief nutshell. As for nutrients, FF's grow big is for the vegetative stage, and tiger bloom/big bloom are for the flowering stage.