By Karen Johnson, U of M Ext. Educator Ag Production Systems, McLeod and Meeker Counties
Soil test analysis data collected from a lawn or garden can be no better than the sample. Therefore, proper collection of the soil sample is extremely important. Representative samples are as important to get good data back for your home lawn, garden, or landscape.
Soil tests can be submitted to a private soil testing lab, or they can be submitted to the University of Minnesota Soil Testing Laboratory. Many local county Extension offices have the submission forms. The informational sheets are listed on the U of M Soil Laboratory website at http://soiltest.cfans.umn.edu/, or you can directly contact the laboratory at (612) 625-3101.
Soil test data can provide data that indicates soil fertility, pH, and organic matter. Fertilizer recommendations are made corresponding to the soil test data. Common tests include phosphorus (P), potassium (K), organic matter, and pH requirements.
Start by dividing the garden/lawn/landscape into areas that have the same soil color and texture. If your lawn or garden has large areas which differ in fertility, take one sample from each area. For example, you may want to sample the front lawn and back lawn separately.
Sample each area for composite samples. Use a garden trowel, spade, sampling tube, or soil auger. Don’t include any surface mat of grass or litter. For an existing garden, the sampling depth should be 0-3”. Gardens should be sampled at a depth of 0-6”. Place the soil samples in a clean bucket. Take several samples within the chosen area. Mix soil well to make one composite sample for the area. Send 2-3 cups of composite sample to the lab. Use a clean, leakproof container (disposable food storage bag or tub) and place in a sturdy mailer or shipping package.
Looking for a video on how to effectively take a soil sample? Visit the University of Minnesota Extension – Yard and Garden YouTube Channel to view three videos on soil testing at http://www.youtube.com/c/UMNExtensionYardandGarden.
While different soil testing laboratories may offer different soil test options, the procedures for conducting the actual tests tend to be similar. Contact the McLeod County Extension at (320) 484-4303 or Meeker County Extension at (320) 693-5275 for availability of submission forms, and soil testing interpretations.