Every gardener has heard it- get your soil tested. But many don’t know why they should do it, how to do it, or where they go to get it done. Here’s the scoop on why, when, how, and where to get your soil tested in Michigan.
Michigan is blessed with a number of soil types. Knowing what type of soil you have in your garden and the basic fertility of that soil lets you make important decisions on improving the soil and choosing plants that will do well in your soil. You don’t want to spend money on fertilizers you don’t need and that may harm the environment. And you certainly don’t want to buy expensive plants that aren’t likely to grow in your soil.
Gardeners should get a soil test when they are new to gardening in an area, when they have never had the soil tested or when they are experiencing a lot of problems growing plants. After your initial baseline soil test it’s a good idea to test your soil every 3-4 years unless you suspect a problem and then you may want to do it sooner.
The most common soil test will tell you the basic soil composition, the pH (see this article on pH) of the soil and the amounts of potassium and phosphorus, major plant nutrients in the soil. It will not tell you how much nitrogen is in the soil because nitrogen is constantly fluctuating. You can also ask to have the percentage of organic matter tested. Soil labs can also test for micronutrients.
A normal garden soil test does not tell you if the soil is contaminated with chemicals like lead or pesticides. This type of soil test can be done but it is expensive.
You can get your soil tested at any time it isn’t frozen solid. The spring planting season is a time when many home gardeners send their soil for testing but that is also the time when you will wait the longest to get results simply because the labs are so busy. Fall is a good time to send soil for testing as is during a winter thaw when you can scoop out soil or very early spring and mid-summer.
How to collect a soil sample
The home gardener can simply dig down to 6-8 inches with a narrow spade. Remove any large rocks and as much surface vegetation as possible and place the sample in a bucket. Repeat this in 10- 20 locations across the garden spot. Larger areas need more samples.
Combine all the samples by mixing the soil together well in the bucket. Then remove 2-3 cups of soil from the bucket. If the soil is very wet spread it on a newspaper in a warm spot and let it get as dry as possible before packing it up. Place the sample in a zip close plastic bag.
Most small suburban lots need to have only one representative soil sample taken. But if you know the soil is different in different parts of your landscape, you have a large piece of property where you will be growing things in different areas, or you suspect a soil problem in one area you will want to do more than one sample. Make sure you label the samples so you know where they came from.
Where to send your soil sample to be tested
In Michigan the primary soil test lab for homeowners and farmers is Michigan State University’s soil lab. Some lawn care services and nurseries offer soil testing but most of them send the soil to MSU anyway. There are some private labs that do soil testing but they generally concentrate on chemical contaminate testing or test soil for large farming operations.
Before MSU’s re-organization it was fairly easy to get a soil test done by going to your own county Extension office with your sample. In some counties that is still being done. They will help you fill out the paperwork, box your sample and send it for you. But after MSU’s disorganization things aren’t that simple for all counties.
Call your local Extension office and ask about doing a soil sample. They may tell you to send your own sample and how to do that or tell you they can do it. If they do it they may sell you a sample box to fill or simply take your sample and fill the box for you, charging you one fee for the box and shipping. Fees vary from $15 to $20 at county Extension offices.
At one point MSU was selling soil test kits through their bookstore but a recent chat with the soil lab at MSU reveals this is no longer being done. Probably the simplest way for a homeowner to get a soil sample done is take the 2-3 cup sample collected and mail it yourself.
First go on line and download the form you’ll need to send with the sample at this location http://www.css.msu.edu/_pdf/SampleSubmissionForm4.pdf Print it and fill it out. Put each sample in a separate plastic bag with its own form attached. Mark the form with a number or letter that corresponds to where the sample was taken from if you have more than one sample and keep a record for yourself.
You can put several properly labeled samples in one shipping box. The post office sells one price shipping boxes you can purchase. Enclose a check for the sample processing fees. At this writing a common home garden soil test is $17, without organic matter testing. Add a dollar handling fee if you don’t have a proper soil test box from MSU for a total of $18 per sample. Your shipping cost is extra, paid at the post office.
On the same webpage where you downloaded the submission form the MSU soil lab has a fee list. If you want the organic matter in your soil tested add the correct amount. It’s a wise idea to consult the fee list before writing your check as MSU has announced they will soon be changing the test fees. They are going to make the organic matter test standard at some point in time and raise the test fee to reflect that.
If you have questions call the soil lab at (517) 355-0218
Send your soil sample to this address;
Soil and Plant Nutrient Laboratory
A81 Plant and Soil Sciences
Department of Crop and Soil Sciences
East Lansing, Michigan48824-1325
You can drop off the soil sample during business hours if you live close to East Lansing and that will save you postage. For a map go here http://maps.msu.edu/files/driving.pdf
Expect your results in about 2 weeks, a little longer during spring rush. A report will be mailed to you with your results and recommendations for soil improvement. A link to a webpage with explanations for what MSU recommends will also be sent. If you are lucky your local Extension office may still have someone who can help you interpret your results.
A simple amendment to change the pH of your soil if needed, the correct amount of fertilizer to add to the soil and knowing your soil type will help make you a super gardener. And you get this information from your soil test. A soil test is worth the time and money.
For more garden articles by Kim Willis click on her name at the top of the page.