After some absolutely non-lovely experiences in community gardens, with people running through and grabbing everything in sight, then dashing off without contributing any work or materials to the plots, I would really really love to see a rentable space. We have real community gardens in my neighborhood, and they are fenced and locked up to protect them from mooching parasites. People can't just go in and do what they want, either--they get a certain space, or they contribute to a planned shared section, with rules and such.
So, how about a rentable space? Perhaps a rental would comprise one four-hour period, enough to grow some crops, especially with guano used. It would make guano more valuable, since people would want to get as much out of their rented space as possible--without having to complete a quest, I would be reluctant to use guano in the current community gardens because, even if I'm standing right there, people are going to rush through with their grabby hands and take it anyway.
Some details:
1. A pre-set time span, perhaps four hours total. If the time is about to run out, but crops are not set to mature until after that time, the renter is given an option to extend the rental period for no more than five minutes after the last crop matures. This extension would be costly enough to motivate the glitch to time things better.
2. Anything not harvested at the end of the span are cleared out. This would allow the implementation of unlimited rental spaces to be available--the space is created upon the spot for each renter, similar to subway cars. Otherwise, we could end up with conflict with not enough spaces for the demand.
3. If the admins wish there to be a limit to renting, then only permit one rental every 12 or 24 or whatever hours.
4. Renters will get a key or ticket or something that will allow them to go back to their garden space within the rental period. Either teleportation could be involved (requiring the same amount of energy as tport) OR the renter would have to walk to the community garden street where they rented the space.
5. The rental fee should ideally not exceed the potential value of crops, but it should be high enough that it doesn't become a replacement for buying a house with that type of garden. There could be different levels of rooms to rent--varying in numbers of plots, with prices that reflect the number of plots.