do you would you usually veg for hydro?

Depends, what kind of plants are you growing? Trees or midgets? Some people go by height, others go by time. What kind of lights are you using?

30 days or abot 15 inches

If you have clones 12 - 18" will yield you about as much as any other size. Seedlings are a whole different thing. Check back if that's what you have.

Herbus

you can 'veg' any where from 2 weeks-2 months...the longer you 'veg'...

the longer the plant will take to finish, and as stated above, if you want big

tree you veg 2 months...if you want nice 3-4 footer, then you if 'veg' 12"-18"

that is what you will get. You see; Your plant will grow 2-3 times it's size during bloom, maybe 4, for pure sativa's...hope this helps.lw