I would have to ask. Do you know what you are doing, because the answers could be different.
where are you at in your preparation to grow...have you started or what?

Be glad to help. start with mild once they are old enough for nutes...this is when the seedlings have 4-5 good sets of alternating nodes and have rooted in your medium.
I could write a grow guide here...so let me know more about your grow history...what kind of lights...etc. know what I mean vern?

the more you tell us that you don't know...The more we can help you. Peace