How to Get Your Soil Tested
Regardless of where you plan to grow your own food - you’re going to want to know what is in the existing soil… and it’s not just nutrient content we are testing for - what you really need to know is - has my soil been contaminated with heavy metals or other toxins?
The reality is that urban grow sites make for some of the most ambitious gardens - they often lie directly in the wake of lead paint and lead fuel usage, proximity to treated lumber, coal, sewage treatment plants, gas stations or other commercial spaces using petroleum, and pesticides. This, along with so many other site specific environmental factors, cause contaminants like lead, zinc, arsenic, chromium, copper, cadmium, mercury, cyanides, and others to end up in city soil. This contamination means the soil and the ground water are in great need of remediation, that is, the addition of organic compost matter to the land. Over time this begins to cut the ratio of these metals and chemicals which are being swept up into the air and into the skin of our city youth and city gardeners.
Some of the most accessible garden spaces in all of NYC lie in the red and yellow zones of this map. Even the green provides a lax estimate of what is ‘safe’ for exposure.
Before you get started with any gardening processes:
Don’t go digging and playing in the dirt just yet. You don’t know what’s in it and you could be unnecessarily exposing yourself to these toxins.
Call your local college's environmental science department to find out where the closest soil testing labs are. Follow their specific sampling instructions dictated by the soil testing lab of your choice. For example here are the detailed instructions on Brooklyn College’s website to collect the sample and send it for testing. This includes digging out several samples from different areas in your space and mixing them together to provide a diverse sample.
Start with a $10 lead test. If it comes back contaminated, then don’t bother looking at nutrient content because this is not soil you want to be gardening in anyway.
Our Experience…
This is the heavy metals test we received in April 2015.
Now compare it to the NYS Dept. of Environmental Conservation’s Soil Cleanup Objectives:
We are looking at the column labeled ‘Unrestricted SCO’ meaning that your heavy metals levels must be below this number for safe produce & livestock to be raised. This includes our vegetable garden and the health of our chickens.
The safe lead level under NYSDEC Unrestricted SCO is ‘63 ppm′
Our lead level read 986 ppm! This was a level too dangerous to touch, never mind grow produce!
Knowing this information gave us a better perspective as to what we were up against in the urban gardening process, and also renewed our dedication to our compost, a waste reduction initiative which we had begun together 6 months prior. We were going to have to start producing a lot of soil ourselves. This is where creating our own compost with the help of our chicken flock became instrumental in remediating our space.