How to Test Soil Samples for the Presence of Organisms
- 1). Dig a scoop of garden soil with a hand trowel. Place the soil on a newspaper and spread it out. Examine the soil for the presence of earthworms, ants, beetles, sow bugs, spiders, mites, centipedes and millipedes. Arthropods, such as millipedes, shred dead plant material so it is more readily available for decomposition. They supply nutrients to plant roots. Earthworms aerate the soil and shed nutrient-rich castings.
- 2). Examine the soil under a microscope or magnifying lens. Organisms seen under magnification include the long spider, wolf spider, pseudoscorpion and predator mites. Tiny organisms such as these eat harmful plant pests such as aphids and spider mites. Beetles and parasitic wasps have been developed for use as commercial biological pest control.
- 3). Send the sample to an alternative soil test lab for a more complete analysis of the microorganism populations.The National Sustainable Agricultural Information Service supplies a list of alternative soil test labs across the country