In Phoenix, Scottsdale really, long ago the community college had plots. In Fairbanks I think the University did, I am not sure about that but in the Alaskan bush some villages provided space.

There is a scheme in some places here which matches people who have gardens they can't maintain with people who have none. Usually they are older people who can no longer cope. Perhaps a notice on the board at the local doctor's or social centre would find you a garden partner? Garden partners

Contact your local Virginia County Extension office to see if they have any ideas for you.

The strategy of doing gardening on someone elses property is actually formalized in some places. The "Fruit Tree Project", which is operating in Portland, New Orleans, and a few other cities, takes care of fruit trees on residential properties where the owner simply doesn't want the hassle anymore. The property owners get all the fruit they want, but the Project gets the rest, maintains the trees, and gives fruit from them out to food banks. Now, I think the property owner does pay a small surcharge upfront. It would be marvelous to see such an effort extended to personal vegetable gardening, though I suspect it would require allowing far more frequent access to the property than would fruit tree maintenance and harvest. It would make sense to at least set up a list-serve, where people with gardening space to offer could link up with people wanting to garden.

Thanks for all the responses. I'm visiting a farm tomorrow to see if the owner will let me rent / use some land for gardening. Thumbs crossed :)

There is a group on the garden web that is local to that area.

I find "Virginia Gardening" in the list, but I thought there was also one for the D.C. metro area. Anyway, asking on a more local garden web forum might help you.

Gardening in Virginia - GardenWeb

Ticonderoga Farms in Chantilly rents plots. $105 for the season for a 10x20. I'm looking for one closer to a Reston but saw TF yesterday!