How many soil samples should I have tested?

Asked March 10, 2018, 12:22 PM EST

If I want to analyze my flower gardens, lawn, and vegetable gardens, do I need to send in 3 separate soil samples?

Newaygo County Michigan

1 Response


Unless the three areas are very close together, it is best to have different soil samples for areas that might have different soil characteristics. There might be differences in soil characteristics, such as nutrient levels, within a property for a variety of reasons: natural variation in soil properties over distance, especially on a large property; differences in land use and management (e.g. farming, fertilization); differences in plant (vegetative) coverage (e.g. wooded area vs grassland); differences in elevation and drainage; etc.

Flowers, turf grass, and vegetables have different nutrient requirements for optimal growth, so these plants deplete nutrients from the soil at different rates. Also, think about whether you have managed these areas differently in the past, in terms of the amount of fertilizer and compost added, etc. If the areas that you want to test have been used as flower gardens, lawn, and vegetable gardens for a while, and especially if they have been managed differently, it could be a good idea to send in three separate samples. We do realize that this can be expensive though, so perhaps you only do one per year. If you choose to combine the soils and send in only one sample, you can get the soil calculator on the website to spit out different results. So for instance, on the website you can "Enter Your Soil Test Details," input the results that you received for a certain sample, then choose a new crop type and generate a custom fertilizer recommendation for the new crop. Thus, you can use one set of soil test results and view the fertilizer recommendations for different crops. However, the recommendations are based on the current nutrient levels in your soil, as well as the type of crop you are planning to plant; you don’t know if the soil test results for one area are accurate for all areas of your lawn and garden.

If the soil test results are not equal between one area of your landscape and another, the fertilizer recommendation for the “other” or new area will not be optimal.

These are things to consider when deciding on the number of soil samples to take.

Hope that helps!

Happy gardening!