No Planting Yet, Get a Soil Test First!

I have a confession to make. My garden hasn’t had a soil test in 10 years. There are plenty of things in the garden, like the chlorosis on the little lime hydrangea and the groundcovers that never seem to cover any ground, that have been telling me now’s the time. I’m finally prepared to listen and only wish I’d done it a whole lot sooner. But with the new side yard bed I told you about last week, I’m determined to do things right. And while I’m at it, I’m going to sample the bed that used to contain my beautiful redbud. It bit the dust last year and nothing in that area, aside from the hosta and solomon seal which could probably survive Chernobyl, is thriving. So I’m double dipping, so to speak.

Most states have a university extension office that you can call or look up online for information on their soil testing labs. And if they don’t have one, they can refer you to reliable labs that will give you a good soil analysis. I visited the University of Illinois Extension’s list of soil testing labs and chose A&L Greatlakes Laboratories. Like most soil testing labs, this one is heavy on agricultural testing, but there’s a tab on the left of the screen called “Lawn and Garden” and if you click that, it’ll take you right to their soil test page for homeowners. Once there, you can choose from two different tests, the basic or the complete.

For $20 per soil sample, the basic test includes pH, organic matter, phosphorus, potassium, calcium and magnesium. Soil tests often don’t include a nitrogen measurement because that number is in constant flux. I could have taken a deeper dive for $10 more, but the basic test will suffice. Factor in the cost of the padded envelope and shipping, and I’m looking at about $50 for the two tests. It’s not cheap, more like an investment, but the window into my soil is invaluable. I want my garden to thrive and getting the soil right is key to making that happen.

But why do a soil test? Soil is soil, right? The short answer is an emphatic NO! Sure things will grow, but they may not grow as well as you hope without a good understanding of what’s happening under foot. A soil test also prevents you from adding unnecessary amendments to your soil which can be both costly and environmentally damaging when it runs off your property and finds its way to the closest storm sewer.

Taking a Soil Sample

Soil testing isn’t a one-size-fits-all thing. Different parts of your garden can have very different soil profiles, which is why I took two different samples. Some labs will provide you with sampling bags but a fresh Ziploc baggie works just fine. The most important thing is that you take a proper sample. Using a trowel, dig down six to eight inches. Once there, lift some soil and add the core of it to a plastic container. Avoid metal containers as they can contaminate the soil. Repeat this four or five times in different areas of the bed, adding each core sample to the container. Stir them together and add about two cups of the mixture to your labeled bag.

Complete the Soil Test Form

Download the sample submittal form and fill it out according to the way you’ve labeled your samples. The soil test also includes up to three fertilizer recommendation options where you can get pretty specific about what will be growing in the area you’ve sampled. For example, if you’re sampling a raised bed for growing vegetables, you’ll select the vegetable garden option. I opted for flowers and broadleaf shrubs since that’s what will comprise both beds.

A quick stop at the post office yesterday and now I wait. The results should be interesting and I’m looking forward to seeing how the two beds compare. The lab says to expect a report within three to four days after they receive the sample. We’ll see. The plan was to do this last fall when the soil test lab was probably pretty slow, but things got away from me and I’m wondering how long it’ll be before I hear something. Hopefully, I beat the spring rush. I’m counting on all those new gardeners last year not knowing about the importance of a soil test. And if you’re one of them, now’s the time to give your garden exactly what it needs. Excellent soil.

I’ll let you know when the results are in and would love to know the outcome of your soil test, if you’ve had one.

Happy Spring!