I totally agree with Change and dst (except the fact that she refuses she was mean there >.>)
To be honest what the community garden lacks is practical activity and excitement. There should be numerous community garden-related quests, activities, etc related to clickables, not just restricted to RL stuff like poems, stories and artwork. Even a monthly quest would do. That would get people more involved in this. But, I'm afraid you need to be much more active for this. The person running it can't expect any more time given to the garden from others, than the time he gives it himself.
Secondly, think of new ideas! The garden has it's own role definitely in this realm, but what is it? I've been here almost a year and all I've seen it garden plots and the shed construction, no real garden role. How about something to, perhaps, grow different kind of resources eg: unidentified plants, toxic plants, aromatic herbs? If an idea is worth thinking and implementing, and you have Council's and Mur's support, it'll help. Make it grow by actually DOing something, not just through words. The garden is something that can help expand MD, if promoted properly.
EDIT: maybe even something to identify the unidentified plants? There are so many possibilities! :)