Want more garden than your small urban allotment? Try what I did. Take a walk around your neighbourhood and look for the weediest or bleakest church/synagogue yard. Approach the pastor or rabbi and offer to take over yard maintenance chores!
Some congregations might even have a budget and pay you for your work, or at least, expenses. The church I work at is very poor, so I bear the expense of perennials, shrubs etc. However, they are classified as donations to the church, so I submit all receipts and am issued a statement by the parish for claiming it on my income tax.
I've been at it for two years now and it's been great.
Mike, do you find that your efforts inspire others -- in the church or community -- to take up gardening?