Most home gardeners know their soil's makeup, be it clay, sandy or loamy. But without testing they may not be able to tell you whether it is acidic or alkaline, and what minerals the soil contains. Many plants grow best in either acidic or alkaline soil, but not both. In addition, nutrient-deficient soil dooms plants before become established. Test your soil to determine its composition, and amend it with any necessary organic materials before planting starts.
Obtain a soil testing kit from your local University Cooperative Extension office or home and garden center, which often sell soil testing kits put together by local agronomists. Choose one that allows you to mail the sample for analysis, as this will give you better results over one that has you evaluate your own sample.
Take a core sample of the soil with a soil probe or trowel. For garden areas, dig down to a depth of 6 to 8 inches. For lawns, 3 inches is sufficient. The soil probe will remove the core automatically. If using a trowel, dig a hole and cut a 1/2-inch-thick slice off the side of the hole with the trowel.
Continue to take samples, working in a zig-zag pattern across the planting area. Avoid borders or transition areas, or areas that have been recently treated with a fertilizer, pesticide or herbicide. While the number of samples needed varies depending on the test kit, it usually ranges from 15 to 20.
Repeat the process for other areas of the landscape, depending on how you are going to use them. You might collect one set of samples for a perennial garden, another for a vegetable garden and a third for turf grass.
Mix one set (20 samples from one area) of samples together in a plastic bucket. Moisten the soil a bit if that helps to mix them. Select a clean bucket that has not been used to hold any chemicals. Remove any large stones, sticks or other plant debris.
Fill the container provided by the kit you purchased. This is usually a box. If there is no container provided, use clear plastic storage bags. Fill out any paperwork required and follow the instructions to mail your samples to be analyzed.