soil test kitSoil test kit

So how do you know if your soil is healthy? Having a thriving garden may indicate healthy soil, but that’s not always the case. Synthetic chemicals can artificially boost plant growth, masking hidden deficiencies and stripping the soil of important elements. Contaminants such as lead may not affect plant health, so you can’t tell whether it’s present just by looking at the plant; however, such contaminants can definitely compromise the health of humans and other organisms that might eat the plant. The best way to help determine your soil’s health is to test it.

There are two main things to measure when testing your soil: soil health and fertility, and contaminants. Knowing how much you have of some key markers of soil health (pH, organic matter, nutrients, etc.), will help you decide whether you need to amend the soil and with what.

Figuring out whether there are heavy metals such as lead or arsenic in your soil will help you decide whether you can grow vegetable crops in the ground, or if you should stick to ornamental plants or vegetable plants in a container. Some soils on sites with lead-painted houses, near roadways, or with a history of certain pesticides (such as lead arsenate) may have “hot spots” with very high levels of contamination. It is always better to test. Do not assume the soil is clean no matter where you live.

Title: Healthy Soils, Healthy Communities: Soil Testing
Organization: Cornell University
Description: Presents the basics of soil testing, including how to decide if it is likely to help you, and provides links to a variety of testing services and a fact sheet on how to interpret results.

Finding a Soil Test
Understanding the Test Results
Finding A Soil Test

A testing facility should be able to help you decide which tests you will need and give guidance interpreting the results. Since soils vary greatly--even within one backyard--you will probably want to take a range of samples in order to get a better understanding of what might be in your soil. Check with the laboratory you will be sending your samples to find out how to prepare your samples and other requirements. Recommendations on how to improve your soil may be specific to what you intend to use the soil for (flower garden, vegetable garden, etc.).

Title: Urban Soils Lab at Brooklyn College
Organization: NYC Urban Soils Institute
Description: This affordable soil testing service is available to gardeners throughout the country. The Basic Soil Quality Test will report on pH; salt content; soil class; NPK (nitrogen/phosphorus/potassium) levels; lead, arsenic, copper, and zinc; and organic content.

Title: Soil Nutrient Testing
Organization: Cornell Cooperative Extension of Westchester County, Elmsford, NY
Description: Our local cooperative extension performs pH tests on submitted soil samples for $18. Scroll down to section B for soil pH test pdf form, which includes instructions for taking and submitting samples. Results are mailed within two weeks. Scroll further for information on additional soil sampling for nutrients.

Title: Cornell Nutrient Analysis Laboratory
Organization: Cornell University
Description: They offer a range of soil fertility analysis packages, as well as total elemental analysis (heavy metal screening), which suggested for home gardeners.

Title: Individual Soil Analyses
Organization: Cornell College of Agriculture & Life Sciences
Description: This lab offers a range of soil tests for nutrients and composition (not contaminants).

Title: How to Take a Soil Sample with Doug DeCandia
Organization: Bionutrient Food Association/Westchester Chapter
Description: A five-minute video showing how to take soil samples for testing.


Understanding the Soil Test Results

Once your soil has been tested, it is important to be able to understand the results, and what it means for the type of vegetation you can safely grow. You may need to add compost or other amendments to grow a healthy soil. [Link “compost and amendments” to section 4.1; link “grow a healthy soil to section 4]. You may want to address any risks of contamination, by focusing on healthy gardening practices instead, that can be found in this section.

Title: Healthy Soils, Healthy Communities: Soil Testing
Organization: Cornell University
Description: Key resources include useful 6-page "Guide to Soil Testing and Interpreting Results."

Title: Healthy Gardening
Organization: Cornell University
Description: Page of multiple resources to help you understand your soil test results and steps to take if your soil is contaminated;

Title: Guide to Soil Testing and Interpreting Results
Organization: Cornell Waste Management Institute 
Description: Complete guide to know when soil testing is helpful, how to take soil samples, and how to interpret the results. Lists the levels of heavy metals, including lead and arsenates. 

Title: Soil Contaminants and Best Practices for Healthy Gardens
Organization: Cornell Waste Management Institute 
Description:  Offers useful information on the importance of understanding soil contaminants, including how plants can become contaminated and best practices to growing and maintaining healthy gardens. 

For specific recommended actions on lead contaminated soils, you can also visit:

Title: Interpreting the Results of Soil Tests for Heavy Metals
Organization: University of Vermont Extension
Description: Offers specific recommended actions on lead contaminated soils.  Lists the levels of heavy metals, including lead, in soil for which the EPA mandates cleanup and discusses best management practices for soils contaminated with heavy metals.

Please note: Lowest levels of heavy metals established by the NY Department of Environmental Conservation (NYS DEC) in the tables, correspond to "unrestricted use", which includes agricultural use.