Planting Success: How to Test and Optimize Your Soil
Before you begin planting this Spring, it’s important to assess your soil conditions to ensure your plants will thrive. Begin by determining the type of soil in your landscape. Knowing this will influence your choices about planting and growing decisions. Soil types vary regionally and geographically and are generally described as clay, sand or loam.
When starting a new garden, consider the type and texture of your soil. One technique is the “ribbon” test, which you can do by hand. Grab a small handful of slightly damp soil. As you squeeze it, force out a strip, or ribbon, with your thumb, pressing the soil into a narrow band. Clay soil will hold together, allowing several inches of ribbon to form without falling apart. Sandy or gravely soil will crumble as you press it. Loam soil, which is a balance of clay and sand, will form a short ribbon that probably breaks apart. Loam is the “ideal” for growing most plants.
Another technique you can do is the dig-and-fill test. Dig a hole about 6-inches deep and 6-inches wide. Look at and feel the material as you remove it from the hole; you’ll notice how moist or dry it is and whether it contains clay, gravel, sand or organic matter. Fill the hole with water and observe how quickly the water soaks into the ground. If the soil soaks up the water so fast that you can’t keep it entirely filled, you probably have sandy soil. If the hole remains filled with water after a couple of hours, you have poorly draining soil that’s mostly clay in nature. If the water drains out of the hole at a moderate pace, your soil is more likely to be loam. Try this test in a variety of areas of your property to see if conditions are the same throughout.
Soil types and amendment tips:
Clay soil – Clay particles are the smallest component in soil, less than .002 mm in size. Closely packed, these particles comprise a heavy, sticky, often soggy growing medium. Clay soil absorbs water slowly and drains slowly, often causing plant roots to sit in excessively moist conditions that can lead to root rot.
You can improve clay soil by incorporating organic amendments, such as compost, planting mixes or well-rotted manure. The organic matter increases the available nutrients in the clay soil. It also enhances the soil’s ability to hold oxygen and enables water to move through it more freely. Some gardeners have found that incorporating finely-crushed rock (such as one-quarter-minus grade) into clay soil will improve drainage.
Sandy soil – Sandy soil holds few nutrients because the sand particles are the largest component in the soil, ranging from .05 to 2 mm in size. Water and nutrients flow quickly through sand, leaving plants poorly irrigated or nourished. Improve sandy soil by supplementing it with organic material, which provides and stores essential nutrients for plants. Amendments like organic compost will also help hold moisture in the plant’s root zone. You can improve sandy soil over time with annual applications of 3- to 4-inch layers of organic compost on the top of the soil.
Loam – Clearly the most desirable type of planting soil, loam is a combination of sand, silt, clay and organic matter (such as decomposed leaves, bark and manure). Loam not only readily absorbs water, it also retains it. It is this “ideal” soil medium that we all aspire to have in our backyards.
Providing the optimal environment for your plants is essential for their success. Understanding the soil conditions and making the necessary adjustments before planting helps to ensure your hard work won’t be in vain.