Soil can be tested any time of the year, as nutrient levels vary only slightly from season to season. Fall and early winter are the best times to have soil tested. The labs are not as busy as they are during the spring and it leaves more time for planning and applying corrective fertilizer and pH adjusters.
When do I need to get my soil tested?
Before planting a new garden or tree or establishing a new lawn, whether from seed or sod
Every three years on established gardens, trees and lawns
Annually when attempting to correct a nutrient deficiency or change the soil pH
When fertilizers containing phosphorus or potassium have been used on a regular basis for a number of years
Coring devices are best for taking soil samples, types include, the Tubular Soil Sampler or the 36” one-piece soil sampler without footstep or with footstep. Augers are recommended on rocky soils such as the 36” soil sampler kit with auger or a power drill with either the 9” Earth Auger or 24” Earth Auger. Use a plastic container with a hole in the middle to collect the soil as the auger pulls it out of the ground. Empty the soil out of the plastic container into the soil sample bucket after each sample is taken. A shovel can be used, but it is not as good as a coring device or auger. If a shovel is used, dig a hole to the proper depth, shave a 1” slice from the side of the hole and save the vertical, 1” wide center portion of this slice.
Take core samples from uniform areas. Avoid known soil differences, such as soil color, texture, slope, limestone and fertilizer spills. Sample these areas separately. In a clean plastic pail mix 8 to 10 separate cores into one sample. Avoid using metal pails, as they contaminate the soil with micronutrients. One sample should not represent more than 20 acres on level, uniform landscapes or 5 acres on hilly or rolling land.
To take a core sample, scrape off surface vegetation or litter and take the sample to the desired depth. As follows:
6” for gardens and lawn establishment
12” at the time of establishment of trees, shrubs and other perennials. Separate the 0 to 6” core and the 6 to 12 core for separate testing to adjust subsoil pH
3 to 4” for established lawns
6” for established trees and shrubs and other perennials
Contact your local Extension office for information on where to send soil samples and recommended tests to have done.