Just updating this thread since I've got some new info. Friend of mine highly recommends these guys:
http://www.organic-farm.com/
They have a store in Causeway Bay that carries their stuff.
Simply Organic
1st Floor
21 Canal Road West
Causeway Bay, Hong Kong
If you want delivery it's weekly. You can ask for a "trial-pack" first time to see what is included and get a taste of the produce before signing up. My friend has been doing this for a while and raves about it. I'm going to sign up now as well...