What is a Soil Test?

A soil test is a process by which elements (phosphorus, potassium, calcium, magnesium, boron, sulfur, manganese, copper, iron, and zinc) are chemically removed from the soil and measured for their "plant available" content within the sample. The quantity of available nutrients in the sample determines the amount of fertilizer or other soil amendments that are recommended. A soil test also measures soil pH, organic matter, and cation exchange capacity (CEC). These analyses indicate whether lime, elemental sulfur, or iron is needed and, if so, how much to apply.  

Why Have Your Soil Tested? 

1. You can encourage plant growth by providing the best amendments, fertilizers, or other soil recommendations. 

When growers guess about the need for lime, elemental sulfur, fertilizers, etc., too little or too much of a product is likely to be applied. By using a soil test report, the grower does not need to guess. 

For Example: Many urban soils already have too high of a pH level, which causes nutrients such as iron, manganese, boron, copper and zinc to become less available to plants. Routinely applying lime will raise pH even higher, whereas adding elemental sulfur will help to lower the pH level. ​

2. It diagnoses whether there is too little or too much of a nutrient. 

Too much of a certain nutrient can be just as detrimental as too little of a nutrient. Knowing how much to add, or withhold for a time, will be of benefit to the targeted crop (lawn, vegetable garden, trees, flowers, etc.). 

3. Promotes environmental quality.

When gardeners apply only as much fertilizer as is necessary, nutrient runoff into surface or ground water is minimized and natural resources are better protected. 

4. Saves money!

Some homeowners routinely apply unnecessary products, such as phosphorus to their lawns. In areas where soil levels are high in phosphorus (which is common), a soil test could save these homeowners money.  
 
The SWCD offers low cost soil testing for lawns and gardens. Most participants are able to easily collect the sample themselves and bring it to the office. Results are typically available in 7-10 days and include a customized report for your growing area (lawn versus vegetable garden versus trees, etc.). 
 
Learn more about the SWCD’s soil testing options, how to collect a sample and more at  www.hamiltonswcd.org/soil-testing 

Example of how pH can change the availability of different nutrients