I don't know much about community gardening or inners cities, but I had a couple thoughts--maybe others will be able to expand on:

Invisible fencing--at zoos they use thin metal cables around pens, it isn't terribly visible from a distance, but it keeps creatures/people contained. If you did something similar, you'd be able to keep unwanted people out while allowing neighbors to see your garden. Or for more privacy, use the cable as support for vines?

Do work with the church--I could see a community garden maybe having 2 entrances, one from the street for say using to unload a pickup of compost etc, and one for pedestrians through the church's property. If you think the street is a problem, keep the gate/door locked & maybe the church could hold the key(s). That way, if the gardeners need to they could just get the key from next door.

Those are my thoughts anyway, hope they're helpful.

I say use some of the youth from the city many of which are up all night involve the more desirable "less desirables" they are part of the community aswell.. you can have volunteer security or put nice flood lights to illuminate the garden over night (crackheads and pros' dont like light) and put up some real or mock cameras and a sign that says "this area under 24 hour surveilance by metro police"

Is the neighborhood really that bad? Yikes! Are you worried about crackheads stealing broccoli? Please don't let possible crime deter you from making a garden. I think studies have shown that when an area is beautified, vandalism drops.

I agree with johnny about inviting everyone to participate, but I disagree about the light. For one thing, it's not good for the plants -- attracts Junebugs, which lay eggs, which become grubworms. Also, I know of a school district that successfully reduced vandalism by turning OFF the lights. Groups hanging around at night don't seek out dark corners. Although they may want privacy for certain activities, they stay close to lighted areas. If it's totally dark, you can't even see where you're going -- nobody likes that!

I wish you the best!

Thanks for the ideas everyone, much appreciated. Johnnygreenthumb, great ideas about the lights and cameras, that acutally might be doable although, I wouldn't want to attract junebugs, does anyone know if they are around in my zone (3a) I've never seen one in my yard, but who knows! The church is actually pursuing a few things in the area with young people, so I might be able to tap into that resource.

Plainjane40, unfortunately, yes, the neighbourhood is really that bad. I'm not worried about people stealing vegetables,(I acutally would be happy about that) but I am worried about people using the garden as a place to dump needles, as well as cans of paint or hairspray. There have been other attemps at community gardens in the area, but these are some of the problems they have come up against. The church has a really good rep. with the city and community, so there is potential to really make a dent at turning things around, we just have to be wise about how we go about it.
Once again thanks for the thoughts, and keep em coming!
PrairieClover

you might look into the south cental garden, better hurry though its about to be bulldozed.

Here is a link that might be useful: SCF

Hi I started a small community garden last year, and I live in the "inner city" of Boston, low income, high crime neighborhood, etc. So far so good. Do work with the church, they sound like an excellent resource. Some of the things we've done here that have worked so far -- raised money to give a stipend for teenagers that participated in a garden internship -- mainly they helped construct the garden over six saturdays in the spring/summer, did a kid's plot, got lots of seniors who were excited about gardening. Also we found that putting up a light source was key in terms of deterring folks from doing drugs/alcohol/have sex in the garden at night. I did have 7 rose bushes dug up and stolen one night, but over all it's been an excellent experience.