ok thats prob what im going to do. that way i wont have to keep ordering seeds to. also if im drying in a seperate location should i buy another carbon filterWhat's better for you? If you stagger them 4 weeks apart, you'll have to mix different nutrient solutions for the separate tents. That's probably no big deal since you're doing aero. If you grow all together you'll have a lot more trimming, drying, and curing to do at once, but you'll only have to do it every few months. If you stagger, you'll need less drying space, but you'll have to dry every month...you'll also have a harvest every month.
I's go with a staggered approach.