Dirt Soil Types Garden Survey Fertilizer pH Testing | The Old Farmer's Almanac

Know your dirt: soil types in the garden

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As you flip through seed catalogs assembling your wish list, think about dirt. It’s the most important element for success with fruit, flowers and landscape plants. Find out what type of soil is in your garden. It affects how and what will thrive for you.

Despite living on a rocky glacier, my gardens thrive. Credit: Doreen G. Howard

Eons ago the Rock River Valley, where I live along the Wisconsin-Illinois border, was carved out by the Wisconsin Glacier, leaving deposits of silt, sand, loam and clay, along with plenty of tumbled rocks and limestone. Because of the glacier action, yards here may have more than one soil type. Mine does.

My acre is at the steep end of a glacier moraine. The front yard is the outwash of the moraine where plenty of silt was deposited. The 18-inch layer sits upon four feet of sandy clay loam. The rest of the yard is the moraine end with an eight-inch layer of loam, on top of two feet of clay loam and more than five feet of gravely loam underneath.

The pH is high, because 40 percent of the soil is calcium carbonate (limestone). The front yard is much lower in lime concentration, only about 16 percent. In short, I have good soil in the front and challenges elsewhere due to high pH

I found this detailed soil analysis at a United States Department of Agriculture website. They’ve mapped the country, analyzed soils and made the data available to all in a free detailed report. Click here to access it.

To use the ap (application), click on the big WWS green start button; then click on Address and enter yours. A map will come up of your neighborhood. Click on the AOI button and place the red box around your yard. Then click on the Soil Map tab and follow directions.

At the end, click on Shopping Cart to order your custom report. Download it immediately or have it sent later via email. It’s free.

Once you know your soil type or types, you probably will have to improve the ground before planting.

Amending a planting hole is a limiting action. Plant roots won’t spread beyond the altered soil. Instead, dig a hole, insert plant and backfill with excavated dirt. Improve the top of the soil in a five to 15-foot radius, depending upon the mature size of the plant. Sprinkle sulfur to lower pH or add lime to raise it.

Work compost, aged manure, straw or grass clippings into the top four inches of ground. Mulch with organic matter such as shredded leaves or wood chips. Nutrients will filter into the soil, enticing new plant roots to grow outward. Perennial and vegetable beds benefit from mixing the materials above into the bed surface before planting.

Let us know what kind of soil challenges you face after you find out about your dirt is at the USDA site. Or, tell us that you have perfect soil, and we can all be jealous!

About The Author

Doreen G. Howard

Doreen Howard, an award-winning author, is the former garden editor at Woman’s Day. She has gardened in every climate zone from California to Texas to Oklahoma to the Midwest. She’s especially fond of unusual houseplants and heirloom edibles. Read More from Doreen G. Howard

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