From the Vine: Soil Testing

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My wife is a baker and bakes many delicious cakes and pies. She makes a dried apple cake, chocolate marble cake, 10-layer chocolate cake, strawberry cake, and buttercream cupcakes. To make these scrumptious desserts she follows a recipe, either from memory or from a secret cookbook. These tasty treats could easily become not so tasty if the recipe was altered. Imagine if she mistakenly substituted salt for sugar or cornmeal for flour.

The same principle of baking and following a recipe should also be followed when fertilizing your lawn or landscape. Why would you amend the soil without knowing what type of fertilizer or how much to add? Overfertilization can lead to excess plant growth, plant disease, plant injury, reduced fruiting, and water pollution. Nutrient deficiency can lead to weak plant growth, stressed plants, plant disease, insect infestation, and poor stands.

Soil testing is a valuable tool when managing nutrients and pH of soil. The analysis can tell you if you have nutrient deficiency or excess, the acidity level of the soil, and what plants can grow best in a certain area. Consistently reliable results can be obtained by only submitting samples to a soil-testing laboratory. The NCDA&CS Agronomic Division will analyze your soil samples free of charge from April 1 – November 30. From December 1 – March 31, there is a $4 fee for each soil sample submitted. For homeowners, the Sampson County Extension Master Gardener Volunteers have put together soil sampling kits that can be picked up at the Extension Office. The soil sampling kits contain 2 soil sample boxes, homeowner lawn and garden soil sampling forms, instructions on how to take a soil sample, and a fact sheet from the NCDA&CS on fertilizing lawns, gardens, and ornamentals.

The soil analysis is only as good as the sample that was collected and submitted. Unique areas should be sampled independently. For example, vegetable gardens, lawns, and trees or shrubs should all be sampled and submitted separately. Collect 10-12 cores from each individual area and mix in a clean plastic bucket. After mixing, fill the soil sample box to the red line on the outer side of the box and label the box in a way that you will know the location of the sample. Once collected, boxed, and the forms are filled out, bring the sample to the Extension Office so it can be delivered to the NCDA&CS soil lab. For more information on soil sampling, refer to NC State University publication AG-614, “A Gardener’s Guide to Soil Testing”.