Soil Minerals and Soil Prescriptions for Organic Gardeners

Instructions for taking a soil sample, and prices for recommendations.

Updated Mar 14, 2010
Why get a soil test?
Soil Test Recommendations and Soil Mineral Prescriptions
By Michael Astera

We charge $45 to make a detailed study of your laboratory soil test and make custom mineral and fertility recommendations for your soil, crops, and climate. This is not a computer-generated report; each soil report is given as much personal time and attention as needed for an accurate assessment and prescription in order to achieve maximum health, mineral balance, and fertility for your garden, farm, lawn or landscape using USDA Organic approved amendments.

Our price does not include the laboratory test; you will need to take a soil sample and send it to the lab for testing and then email the test results to us.

Instructions for taking a soil sample:

You only need to send 1 cup of soil, approximately 8 ounces (225 grams). The goal is to get a representative sample of your soil 6" (15cm) deep. This is the aerobic zone where most root growth and nutrient exchange happens. You want to take several samples of the area and mix them together. As a rule, you would take six to ten samples of any area that you are going to treat the same, while avoiding strange or unusual areas or sampling them separately for a separate test. Clear the surface area of loose duff and organic matter before you take your sample. Dig a hole six to eight inches deep with an ordinary shovel, then take a thin slice straight down along one side of the hole. This slice is your soil sample. Use a clean shovel to do the digging.

Take as many samples as you think necessary and mix them together thoroughly in a plastic or stainless steel container, removing large roots, stones, or chunks of organic matter, then take about one cup of this mixed sample and place it in a clean plastic or heavy paper bag to send to the soil testing laboratory. If the soil is extremely wet when you take the sample, spread it out in a warm place and let it dry until it can be handled without leaving mud on your hands.

Where do I send the soil sample?

We recommend Logan Labs in Lakeview Ohio as we have worked with them for a number of years and have found them to be fast, dependable, and accurate. Logan Labs’ website address is You should contact them before sending your sample to arrange payment.

Logan Labs, LLC
620 North Main Street
Lakeview, OH 43331
Toll Free: 1-888-494-SOIL

The test you want is their Basic or Standard soil test, which costs $20 [March 2010] and includes: pH, organic matter, base saturation, "Total Exchange Capacity”, Mehlich III extractable Sulfur, Phosphorous, Calcium, Magnesium, Potassium, Sodium, Boron, Iron, Manganese, Copper, Zinc, and Aluminum.

Logan Labs will provide your soil test results in a PDF format. Email the results to us at along with a short description of your growing area, soil type, what you are growing, and any special problems or goals. See sample questions Here.

When we receive your soil report we will send you a PayPal invoice for $45 for each soil Rx you are requesting and begin writing your soil's custom fertility prescription.

The entire process from mailing the soil sample to the lab until getting our recommendations normally takes about two weeks. Questions? Email us at

We will be glad to answer any simple questions about your soil prescription by email.  If you need more extensive written consultation our rate is $45 an hour.  We do not offer telephone consulting, via email only.

More Soil Testing Labs

Below is a short list of other private soil testing laboratories that we have used in the past.  There are many other good soil testing labs around the USA and the world.

If outside the USA, do a search online to find your best options. Those outside the US who wish to send a soil sample to a US Lab will need to download the USDA import permit and attach it to the outside of your mailing envelope or box, as well as to the bag you are mailing your soil sample in.  The printable PDF form is here: USDA Permit

What you want is what is commonly known as a "complete soil test".  The results of this test give an excellent overall picture of the soil's mineral balance.  A "complete" or standard soil test tests for: 11 essential nutrients: Sulfur, Phosphorus, Calcium, Magnesium, Potassium, Sodium, Boron, Iron, Manganese, Copper, and Zinc, and also for:
organic matter
total cation exchange capacity (Ca, Mg, K, and Na)
and % of base saturation of: Calcium, Magnesium, Potassium, Sodium,and exchangeable Hydrogen

Soil Testing Laboratories USA:

Logan Labs LLC:
(Logan Labs uses the same soil report format that uses in our examples on this web site and in our Ideal Soil book)

A&L Eastern:

A&L Western:

Brookside Laboratories:

Soil Testing Laboratories Canada

A&L Canada:

Please contact the soil testing lab of your choice for prices and any special instructions.

Soil Fertility Rx $45.00 US
Send Your Soil Test results to: and we will send you a PayPal invoice for $45.

We use only PayPal for all orders. 

When we get the results of your soil test we combine them with any other information that you give us and make recommendations based on what you are growing.  Unless you inform us differently, all of these recommendations will be for amendments and cultural methods that are approved under the USDA National Organic Program. Here are samples of the results and recommendations for this test.

Your results and recommendations will be sent by e-mail as a .pdf file.

Expect your recommendations in 7 to 10 working days.

Questions?  e-mail us at

Or, if you would rather do it yourself....

Another option for many growers, and one we highly recommend, is to pruchase a copy of our new book The Ideal Soil: A Handbook for the New Agriculture and learn to interpret your own soil test results and write your own prescription and recommendations.  The Handbook is available in both hardcopy and ebook versions. The price is $29.95 US, plus mailing for the hardcopy..  With this book you will never need a soil consultant again--you will be one!

The Ideal Soil:
A Handbook for the New Agriculture

new from

Teaches all you need to know to become your own soil minerals expert!
(Yes, really)

Featured Farmers:
Wendell Berry Community Garden
Olympia Washington USA
"The first urban agriculture project of Sustainable South Sound."


John O'Brien, one of the movers behind the Wendell Berry Community Garden on Olympia's east side told us, “This [soil test and prescribed fertilizers] is the best investment expense we made there.”

"We followed your recommendations to the letter and got a yield of over 30,000 lb/acre."

"We not only got superior yield of our vegetables, the quality and taste was/is outstanding. Many members are still eating output from our freezers, dryers and canning jars.  The few *Brix readings I took on the produce were good to excellent, compared to all poor to middlin' for everything from the Olympia Farmer's market."

Note that there are no holes in these cabbage leaves.

"We were fortunate last year. We used no pesticides of any sort, unless you count blue sticky cards, but that was mainly to monitor little flies. Our only real pest pressure was some fungal disease on eggplant. We contacted fungi perfecti, where some of the employees had good results with a mycogrow formula which contained a mycorrhizal species not in the powdered form. I applied with a bit of kelp & fish emulsion & the crop was saved. We're expanding the garden by 50% in area and 5 new members this year, and Sustainable South Sound the non-profit umbrella agency has put together 28 workshops on sustainable living. I'm teaching one on growing nutrient-dense food."


Wendell Berry Community Garden home page

Contact John O'Brien

Welcome to the Wendell Berry Garden on facebook


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