Gardening on a demolished lot?

There is a lot near my home which used to be a school I went to, until 5 years ago when it was all demolished and torn up, and has since been vacant and quite overgrown with foliage.

I've always wondered how viable it would be to start a community garden or something on lots like these.

There are also many abandoned factories, shops and now even shopping malls around here which could one day be demolished.

One big concern would be contamination from lead, asbestos, mercury, etc. I heard there are some plants that can slowly get rid of such contaminants?

And then there is compaction from all the concrete and asphalt...

Is there anyone who has successfully gardened on such lots, or are they such a hassle it's best to let them go wild?

Sounds like the empty lot has had five years to “go wild” and heal itself. If you can identify what plants are growing naturally, we can probably determine what soil conditions are supporting that plant life. Some plants are very deep rooted and could be pulling up minerals, breaking up and aerating the compacted soil. Any fungi showing up? Mushrooms could be remediating problems naturally. Also, what is happening with water runoff? If the water is percolating through the soil, and plants are growing, problems could be resolving themselves. If water is running off the property, oily materials that float could be washing away. Careful observation of what nature is doing by itself could reveal a lot about the growing potential of this land.
Speaking from experience, this former 1 acre village dump site where I now work the land now supports 50 deep rooted trees including 25 fruit and nut trees as well as 300 sq ft of annual veg, and innumerable native perennials. It feels like rehabilitating this land has become my life's work and it is, most days, very satisfying to see the recovery.
Best wishes in realizing your community garden vision Nicholas.

It's a good idea, and worth pursuing.

For a community garden, I think it's just about mandatory to have soil tests done. This is both for public safety and liability reasons.

Many urban areas have an application process for community gardens that will guide you through the requirements and help you jump through the hoops.

Quite often  this needs to be done by a registered community association rather than an individual.

In Chicago there are many community gardens on vacant lots, often even on concrete.  They almost universally use raised beds with imported soil.

Vacant does not necessarily mean abandoned.  Be sure to make every effort to contact the owner to ask for permission.  Use GIS services, tax records, google, whatever you can.  If you do get a hold of the owner and they are agreeable, a long term dollar (or more) lease would be ideal. There may be abandonded property laws on the books, but if you choose to operate under one of these laws be absolutely sure you have a right to the property.  If you choose to go guerrilla, be aware the owner could show up at any time and charge you with trespassing, vandalism, and block your access to the soil and perennials you have carefully cared for over years.  

There are several accounts of people building wondrous gardens on “abandoned” private and public property, just to be kicked off when the owner decides they don’t want them there for whatever reason.  Don’t make that mistake.

Gray Henon wrote:Vacant does not necessarily mean abandoned.  Be sure to make every effort to contact the owner to ask for permission.  Use GIS services, tax records, google, whatever you can.  If you do get a hold of the owner and they are agreeable, a long term dollar (or more) lease would be ideal. There may be abandonded property laws on the books, but if you choose to operate under one of these laws be absolutely sure you have a right to the property.  If you choose to go guerrilla, be aware the owner could show up at any time and charge you with trespassing, vandalism, and block your access to the soil and perennials you have carefully cared for over years.  

There are several accounts of people building wondrous gardens on “abandoned” private and public property, just to be kicked off when the owner decides they don’t want them there for whatever reason.  Don’t make that mistake.

I'm not one to try guerrilla gardening, I was going to contact the owner about a lease. Even if he declines, there are some other places that have been vacant for even longer. And I've heard people complain about all these vacant, unkempt properties, so I really think it's beneficial to put them to some kind of use.

I bought a lot like this.
Make sure you know the rules for urban agriculture in your location, or you might end up being fined.
Because of the difficulties that the soil presents,  raised beds are what I use.
Evidently plants concentrate heavy metals in their greens, not their fruits, so the of thing I plant in the ground is nut and fruit producing perennials.

Water and to a lesser extent electrical service can be hard to do without.

Chipdrop or the equivalent can be your best friend when it comes to filling beds.

Nicholas said, " There is a lot near my home which used to be a school I went to, until 5 years ago when it was all demolished and torn up, and has since been vacant and quite overgrown with foliage.

Since this was a school, it may be owned by the school district or the city so if I was wanting to do this I would contact the school district first about starting a community garden.  I bet they would feel this is a great idea or let you know their plans for the lot.

If you get the okay, are their rules for starting a community garden?  Check with the city to see if they require a license or a charter.

Anne Miller wrote:Check with the city to see if they require a license or a charter.

Agreed, this is an important preliminary step.  Around here, some kind of registered community association is just about mandatory.

Since there will be public access, the property owner will want proof of liability insurance.

This is such a great thing I hope starts to pick up around the world. In every city, there are lots sitting empty that could be turned into productive land that can feed the community rather than being an unused drain on the community.

In this county and I assume many across the country you can access the Deed Recorders info online. Google the page with your county in the search. On the search page here it asks for the street name. Once you find the correct street the results are in house number order; except that empty lots are at the beginning. Since your lot was recently built on I'd guess it would still have a house number. I'd also guess that the school district still owns the property. If they had sold it there's usually a news story about an upcoming auction. Here the info for the property has the owners name and an address that the tax bill is sent to; which in most cases is the mortgage holder or their agent.

If the school had a basement then the fill would be the bricks and blocks used in construction of the building and then dirt would be brought in to fill the lot to grade. If the school was built on property with a hill; then the fill would likely be "clean dirt" from the hill.

I've rented abandoned property from the city and they are thrilled to get someone to use the property. They asked me what I'd pay in rent and I said $10 a year and they accepted. That was many years ago, but they might still take anything you offer - for a rental. Remember though that you'll then be responsible for maintaining the property which might be mainly mowing.

Novella Carpenter of Ghost Town Farm in Oakland CA https://www.novellacarpenter.net/ wrote about the way she and some other local urban farms/gardens dealt with those kinds of challenges, including testing for contaminants, removing the fallen leaves of trees that were contaminated in order to prevent them from breaking down and reintroducing the heavy metal back into the soil, and other issues with utilizing non-conventional growing spaces. They did a lot of seat-of-your-pants learning in the books she wrote but I found it to be really helpful and interesting int he specific context you are describing, ie "abandoned, possibly contaminated, urban. There are some amazing productive community gardens in that area as a result of some of the efforts she describes so it might be worth reading a couple of her books to get a feel for the type of project you are thinking about undertaking.

FWIW, I have seen a lot of community gardens on similar lots in the urban area where I live.