One of the starting points of any organic lawn care program is getting to know your soil. A soil test is a useful tool that indicates the acidity (pH), the presence of main nutrients (nitrogen, phosphorus and potassium), micronutrients (magnesium and calcium), salt saturation and organic matter. It will point out any important deficiencies which may need to be corrected.
Well my soil test came in providing some interesting information. It turns out my organic matter level was acceptable, not great but not as bad as I thought. It looks like leaving the grass clippings on the lawn really does help. As my level was at the low end of acceptable, I did decide to top-dress with compost this year to give my new organic program a boost. Adding more organic matter will also increase the capacity of my soil to retain water with less watering.
My soil test showed that my soil had a high pH (7.4). Turf grasses like a soil pH between 6.5 and 7.0 which is slightly acidic. Proper pH levels help ensure that your lawn is able to take up the nutrients present in the soil. My high pH means that I will need to add some elemental sulfur to lower the pH. Lowering the pH will take time and will be affected by factors such as irrigation which can increase the soil pH. Lowering the pH will not only help ensure healthy turf but will help with weed control since dandelions thrive at a pH level of about 7.5. (Other weed indicators are clover and medic, the presence of which may indicate your soil is nitrogen poor, and needs compost or a nitrogen fertilizer). If your soil test indicates your soil is too acidic, you may need to add lime.
My test also indicated that my soil was deficient in potassium (K). Potassium enhances root development and branching, helps improve drought, heat and cold tolerance, improves disease resistance and aids in wear tolerance. Given the recent history of hot dry summers in our area, improving drought tolerance is critical. As a corrective measure, I will add potassium magnesium sulphate which will 1) add potassium to sort out my potassium deficiency and 2) balance my potassium-magnesium ratio which will hopefully improve the chlorophyll production ability in my lawn thereby producing a greener lawn without excessive top growth.