Having a classic swath of lush, green grass surrounding the home is a goal of many homeowners. Some lawns live up to that goal, while others struggle. Important to that goal is good soil. While some gardeners are lucky enough to have perfect soil for growing grass, many others will have to work harder to achieve it. A soil analysis is a key part in achieving the right soil for your lawn. Get a soil analysis whenever you establish or renovate a lawn.
Soil analysis is important for achieving optimal growing conditions for your lawn. Healthy grass requires good drainage and organic matter. Heavy feeders, lawn grasses also require good amounts of soil nutrients. Many properties lack the structure and nutrition grass requires. A soil analysis is the only way to accurately assess what amendments your lawn requires.
Taking a Sample
Take about 10 to 12 small samples from various locations in the lawn. Mix the soil thoroughly in a bucket and remove about 1 cup to send to the lab. The sample can be damp, but not wet. Place the sample in a plastic zipper bag or a bag provided with a soil kit and send to the lab.
The analysis will contain several facts regarding your soil. The first is soil pH. It will also include basic nutrient content, including nitrogen, phosphorus and potassium (N-P-K), and usually iron. You will be told if the various nutrient levels are low, medium, high or excessive for growing grass. Some labs will also test for micro-nutrients, such as magnesium and manganese. At your request, they will tell you the amount of clay, sand, silt and organic matter, helping you improve structure. Many labs, also at your request, will also make recommendations on soil amendments.
Soils which are heavy in clay and silt will need to be amended with organic matter to improve drainage. Added to sandy soils, it will retain moisture. Organic matter is important in holding and releasing nutrients to plant roots, as well as aerating soil and providing a healthful environment for worms and beneficial microorganisms.
Soil pH and Nutrition
The ideal pH for most lawn grasses is between 5.5 and 7.7. Add iron sulfate or aluminum sulfate to lower pH. Add pulverized limestone (lime) or dolomitic limestone (dolomite) to increase pH. Never modify pH without a soil test, which should be done every three to five years. The correct fertilizer formula can be used once the results are in.
Finding a Lab
Many state and provincial cooperative extension services provide soil testing. Contact your county extension office for a soil test kit or instructions for sending a sample. There is usually a small fee for the service, which varies depending on the services you request. The lab will want to know what you intend to grow, and which tests you require.
Soil tests are available at garden centers, but are usually limited to testing for pH. Most other soil analyses will have to be done by a lab.