what plants are you going to grow? if you want a strain that doesn't have an easily recognizable odor i highly recommend th seeds s.a.g.e. it smells like sweet grapefruit. not like weed at all!
Assume it's going to smell strong, and plan for it. Some of mine smell so strongly you can taste them - others, not so bad. Better to err on the side of caution until you're sure, though.
a couple air filtering units that have carbon filters will help alot. Just make sure it's carbon filter and not a room deodorizer with aroma. a couple tabletop units bring down the smell in my room alot.
I'm growing 1 auto white dwarf right now.. so I don't think that the smell will leak into next door. I was thinking about growing 1 more plant but if I can get away with not having to buy filters and shit I will just stick to the one. Although I'm almost quite certain my neighbors smoke weed. I just don't want anyone knowing my business.
Thanks to all that replied.. you really helped me out!