How to test garden soil

How to take a soil sample to test for toxins nutrients, organic matter

Shop for tools that will help you take a soil sample!

How to find a lab to test your soil

In the US regional gardening extension services can direct you to the best local soil testing lab click here for a link. An extension service is a partnership between the US government and universities to provide agricultural and gardening services to citizens

Why test soil?

Testing soil is particularly important if you are new to a site. It’s the best way to learn if soil is toxic and  what nutrients you are working with and what you need to add to grow healthy plants.

How much does a soil sample cost?

The price of soil tests vary depending on the lab. They are generally about $45

How long does lab testing take?

Lab turnaround ranges depending on the lab and often the season, 2 weeks is standard, but often you can pay a premium for faster results

Can I test my soil at home?

Soil pH can be tested at home see soil pH here

You need to take a soil sample and send it to a lab to test for nutrient balance,  verify levels of organic matter and concentrations of heavy metals

Do not trust soil test kits that claim to reveal toxicity or nutrient balance, sophisticated lab tests are needed to determine these factors

Taking a sample for a lab test

Wear gloves, if you’re concerned wear a face mask, because they will help protect you from toxins potentially hiding in your soil.

Use a trowel to take small samples of soil from 10 or more spots in the area of your garden you would like to know about, the samples should be taken from 2-8 inches down because the lab will need a diverse sample of soil.

Put scoops into a clean container remove any rocks, roots, leaves or garbage.

If wet, let dry. Do not heat as it may change the readings

Mix contents until well blended

Fill a plastic sample bag with .5lbs of soil (about one cup)

Write your name and date on the bag

If required by the lab, fill out an order form indicating the types of tested you would like for your soil

Place plastic bag in a mailing envelope or small box

Mail sample to a lab

Expect about two weeks for results spend the waiting time planning your gardening or start amending your soil!

What’s the best time to take a soil test?

The best time of year to perform a soil test is the fall so you have the winter to correct any deficiencies

Soil tests are recommended every two years as your soil is always changes, depending on what you put in it and what plants take out of it

Where in the garden are the problematic conditions?

Soil contamination tends to occur in patches, sometime one side of a garden will be free of toxins while the other will have many.

Keep in mind that contaminates drift through the soil over time.

If your test comes back showing questionable levels of contamination you should do further testing and begin soil remediation learn more here.

The top 1-2 inches of soil tend to be more contaminated than deeper soils.

A sample targeting the top two inches of soil can help determine if you have a heavy metal contamination.