Soil Sampling For Home Landscape and Garden Developed by: Dr. Teri Hamlin Georgia Department of Education

Purpose Determining the fertility level of a soil through a soil test is the first step in planning a sound lime and fertilization program for the home landscape and garden. This step leads to higher plant yields and quality by following recommended application rates.

Purpose A soil test provides the means of monitoring the soil so deficiencies, excesses and imbalances can be avoided. Many Georgia soils are low in pH and one or more of the essential plant nutrients. to maintain normal plant growth, lime and fertilizer must be supplied in sufficient quantity to meet the plant's requirement. A soil test will determine the soil's contribution to the plant requirement, with lime and fertilizer supplying the remainder.

Maintain Soil Fertility Soil testing is any chemical or physical measurement that is done on soil. It is indispensable in establishing and maintaining a Soil Fertility Program. Soil fertility is the potential of a soil in terms of the amount and availability of elements and nutrients necessary for plant growth and development. Providing satisfactory recommendations based upon tested soil depends upon three factors: representative sampling, accurate analysis, and proper interpretation of the analytical results.

The Soil Testing Laboratory Soil tests such as those conducted by the University of Georgia Soil Testing and Plant Analysis Laboratory will help you develop and maintain a more productive soil by providing information about the fertility status of your soil. The Soil Testing Laboratory is located on the campus of the University of Georgia at 2400 College Station Road in Athens. It is equipped with the most modern instruments available for rapid and accurate soil analysis. Analysis results and fertilizer recommendations are returned to your county extension agent for dissemination and adjustments, if necessary. The laboratory offers a number of tests to meet specific soil and cropping circumstances.

Lime & Fertilizer Recommendations Information from a soil test will help you select the proper liming and fertilization program to obtain optimal growth of lawn, garden and ornamental plants.

Procedure One of the most important steps in soil testing is collecting the sample. Soil test results can be no better than the sample submitted to the laboratory for analysis. A soil sample weighing about 1 pound is used to represent thousands of pounds of soil in the landscape or garden. Therefore, it is extremely important that soil samples be properly and carefully taken.

A Good Soil Sample Should Be Representative of the Area Areas that have been treated differently should be sampled separately. In the above example, four samples should be taken -- one each from the garden, the lawn, the ornamental shrubs in the landscape, and the azaleas. If the front and back lawns have been treated differently or if they are seeded to different grasses, take a separate sample from each.

Procedure Take soil from a minimum of 10 random locations (x) in the sampled area and mix together in a clean bucket. For trees and shrubs, take soil from six to eight spots around the drip line of the plants and mix.

Do Not Contaminate the Sample Use clean sampling tools and containers. Never use tools or containers that have been used for mixing or applying fertilizer or limestone. A small amount of residue on containers can cause serious contamination of the sample.

Sample to the Proper Depth Remove any surface litter such as turf thatch or mulch. For lawns, sample to a depth of 4 inches. For gardens, ornamentals and fruit trees, sample to a depth of 6 inches.

Tools Use a trowel or sampling tube to collect soil samples.

Tools To use a trowel or spade, push the tool to the desired depth into the soil. Then push the handle forward, with the trowel or spade still in the soil, to make a wide opening. Cut a thin slice from the side of the opening that is of uniform thickness -- about ¼ inch thick and 2 inches wide, extending from the top of the ground to the depth of the cut Scrape away any grass thatch or mulch, and place the slice of soil into a clean bucket or other container. After the soil is taken, remove the shovel or spade and let the soil fall back in place.

Soil Samples Should Be Carefully Mixed and Packaged All cores taken for a given sample should be collected in a clean bucket and thoroughly mixed.

Soil Sample Bag Fill the soil sample bag to the indicated line with the mixed soil. Supply all the information asked for on the soil sample bag. List your Name and Address, Plant to Be Grown, Sample Number Do not use sample bags other than those provided by the University of Georgia Soil Testing and Plant Analysis Laboratory. This information is essential for the return of your sample results and fertilizer recommendations to the proper county extension office.

Soil Sample Bag On the bag, indicate tests desired by checking the proper box. For lawns, gardens and shrubs, a routine test will suffice. If a special analysis, e.g. nitrate-nitrogen (NO3-N), organic matter (O.M.) or boron (B) is needed, first consult your local county extension office.

Laboratory Tests and Fees Routine Tests: pH, L.R., Soil Test P, K, Ca, Mg, Mn and Zn Micronutrient Tests: Boron (B) Other Tests: Organic Matter Content, Soluble Salts, Nitrate Content Commercial Greenhouse or Nursery Soil Test: pH, Soluble Salts, NH4, NO3, P, K, Ca, Mg The laboratory charges a nominal fee (subject to change) for these analyses. Please contact your county extension office for the most recent information about current fees

Routine Test for Lawns & Gardens Routine Test: pH, Lime Requirement (L.R.), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Manganese (Mn), Zinc (Zn) Routinely recommended for all commercial field and vegetable crops as well as home lawns and gardens

County Extension Office Samples should be dropped off at your county extension office for mailing to the laboratory. Soil sample bags are available at your county extension office.

Soil Analysis Lab Sample Receiving The soil samples are organized in a set of 100 and are logged in with lab numbers in the order they are received. Even though the samples have numbers and letters given to them by the farmer or home gardener, the lab assigns each sample with a unique lab number so it is easier to keep track of them within the lab.

Soil Analysis Lab Preparing the Samples for Analysis - A "blank" and two "check" samples are placed in each set for quality control. The blank is space left in the group where there will be no soil but only the chemicals which are added for extraction. At the end of the process, when the plant nutrients are analyzed, all the nutrients in the blank "sample" should read zero. The two check samples (in this case checks "D" and "F") are soils with a known nutrient content. When they are analyzed, they should give nutrient levels within a certain numerical range. Notice the range of colors of soil from the same state.

Soil Analysis Lab Drying Racks – The samples are dried at room temperature with a fan or at a low temperature (if they are very wet) on drying racks The low temperature is used to eliminate possible volatilization of the essential elements.

Soil Analysis Lab Grinding the Samples – With one pass through a "grinder" each sample is broken up and sieved through a 10-mesh screen

Soil Analysis Lab Checking the Forms – The order of the samples is double checked against the sample submission forms in each set. The forms are then taken to the data processor who enters the name and address information along with the lab numbers into the database. After the samples are analyzed, the data is electronically merged with the other information from the forms to generate the final soil test report.

Report Report Format – The report for each sample includes results, calculations, and recommendations and comments for up to four crops or landscape areas. Recommendations can be obtained in lbs/acre or lbs/100 or 1000 square feet by using different crop codes.

When and How Often Should Soils Be Tested? Soils can be tested any time during the year; however, be sure to sample well in advance of planting or spring green-up. Generally, fall is the most desirable time to sample soils, because landscapes and gardens are usually dry and easily accessible. This is particularly important on areas where lime is likely to be needed. Lime reacts fairly slowly and should be mixed with the soil several weeks before planting. Soil nutrient levels change during the year depending on the temperature and moisture content of the soils. It's important, therefore, that samples be taken at or near the same time each year, so results from year to year can be compared.

When and How Often Should Soils Be Tested? Soils should be dry enough to till when sampling. Once medium or high fertility levels are established: lawn and ornamental areas only need to be sampled every two to three years vegetable gardens should be sampled every one to two years If wet samples are collected, they should be air dried before being placed in the soil sample bag.

Record Keeping Keep previous soil test results for each area and refer to them when you plan limestone and fertilizer applications. Periodic soil sampling of each area will help determine whether you are following a soil buildup or soil depletion program. If a sound soil testing program is not followed, a deficiency or an excess in fertilization rates can result. The fertility level of a soil is similar to a bank account: If the amount deposited exceeds the amount withdrawn, there is a net buildup of the account. If the amount of nutrients applied in fertilizer and limestone exceeds the amount removed in harvested crops and the amount lost by leaching, there will be a net buildup of the soil fertility level. If the opposite is true, the fertility of the soil will decline.

Final Results By sampling and determining the fertility level of a soil Applying proper amounts of lime and fertilization Result in a healthy home landscape and garden