Publication Number: 452-129; Posted June 2002
Sample established areas-lawns, trees, shrubbery, and other perennials- - at any time of year; however, an ideal time to take samples is when the garden season has ended in the late summer to early fall. Sampling in the fall allows time for corrective pH and nutrient management before new growth starts in the spring. Fall sampling also avoids a sometimes busy spring period at the Soil Testing Laboratory, thus avoiding delays in getting your soil test results.
If an established area exhibits abnormal growth or plant discoloration, take a soil sample right away. For areas recently limed or fertilized, delay sampling at least six to eight weeks.
A soil sample is a composite of numerous sub-samples, so a soil that is too wet will be impossible to mix together. As a rule, if the soil is too wet to work (or is good for making mud pies like in the photo!), it is too wet to sample. Another way to judge is to squeeze soil into a ball. If it easily breaks apart, then the soil can be sampled.
How often should a soil be tested? If you live in the Coastal Plain region and have sandy soils, it is best to test every two to three years. The sandy soils in that region do not hold nutrients as long as soils in the other parts of the state and are more likely to become acid through the addition of nitrogen. The nutrient levels in the silt and clay loam soils of the Piedmont and Mountain regions change less rapidly with lime and fertilizer applications. In these areas, soil testing once every four years is usually sufficient.
Before we proceed, let's see what you learned about when to take a soil sample!
Select the true statement concerning when and how often to soil test.
2. Soil samples for established plantings should only be taken before new growth in the spring.
3. In Virginia, landscape areas should be soil tested approximately every two to four years.
4. Soil sampling immediately after applying fertilizer will give the most accurate soil test.
