A soil test is essential to maximize yields in gardens, said Shaun Francis, University of Arkansas at Pine Bluff Extension Program horticulture specialist.


A soil test not only reveals which nutrients are needed, and in what quantities, but also whether or not the soil pH should be corrected. This is important because if the pH level is not in the correct range, plants cannot take up nutrients in the soil, he said.


Soil sampling provides the most efficient use of nutrients thus maximizing fertilizer and lime application dollars.


Excess nutrients waste money and compromise the environment through groundwater contamination, Francis said. Careful soil testing and correction ensures that each crop gets exactly what it needs to grow and yield its full potential, while protecting the environment from contamination by runoff and the leaching of excess fertilizer.


Tools needed for a sample collection include a clean bucket, a soil auger, a hand trowel, a pen or waterproof marker and a soil sample box that can be picked up at a county Extension office. Collect a representative sample by randomly collecting at least 25 soil cores from each sample area using the soil auger.


However, avoid taking samples from nontypical or abnormal spots such as close to a fence or where one handled fertilizer or have a compost heap.


Using a hand trowel, mix the soil thoroughly in a bucket to form what is called a composite sample that should represent no more than 20 acres. For home gardens, five to 10 soil cores would be sufficient to form a composite sample.


The soil lab report provides recommendations for nutrients and lime for pH correction. Recommendations will be given in pounds per acre, which one must convert to pounds of a manufacturer’s mixture.


The county Extension agent can help residents do so and also suggest alternative fertilizer combinations that may match recommendations, which could save them money.


Although soil sampling can be done at any time of year, Francis suggests that the ideal time to do so is about three months before planting. This allows time to work the soil, adjust the soil pH and add any organic material if needed, he said.


For more information on soil sampling or help interpreting the soil sample results, contact a local county Extension agent.


The University of Arkansas at Pine Bluff offers all of its Extension and Research programs and services without discrimination.