Soil PH, Sulfur & Lime
Soil PH is an important chemical property because it affects the availability of nutrients to plants and the activity of soil microorganisms. Soil PH is a measure of the acidity or alkalinity of the soil with a scale of 0 to 14. The neutral point or balance for soil PH would be 7. As the number of the soil PH increases this indicates an increase in soil alkalinity. As the soil PH number decreases this indicates an increase in soil acidity. The ideal PH for most grass types is 6.5 to 7.0. This would be an optimum PH but different grass types can tolerate a range of PH levels.
Facts About Sulfur
If your soil tests indicate too much acidity, then you would need to add lime to increase the alkalinity to reach your target PH. If your soil test indicates too much alkalinity, then yu would add sulfur to increase soil acidity to reach your target PH. Please note that lime and sulfur can take up to 2 – 3 months (or longer) to react with soil. The soil PH should be tested again at this point in time and may require that the soil be treated again — so be sure to allow for this extra time when planning your grass planting. You will need to work the lime or sulfur at least 6 inches into the soil for the best and quickest results. It is highly recommended that a professional soil PH test be performed before you attempt to adjust your soil PH. This soil test can usually be obtained through your County Extension Agent (source: Lawnfertilizers.com)
Facts About Lime
What is lime? Lime, in the sense of applying it to a lawn, is pulverized limestone or chalk. The main component is calcium carbonate. Lime with a high calcium content is referred to as calcitic lime and has the added benefit of adding calcium to the soil. Some limestone contains a significant amount of magnesium and is referred to as dolomitic lime. Dolomitic lime adds magnesium to the soil and could be used if soil tests indicate a magnesium deficiency. Pulverized lime is powdery and messy to apply, often causing lime dust to blow everywhere. Pelletized lime is more expansive but is made into dust-free pellets which dissolve with subsequent rains or irrigation.
Why lime? You may need to add lime to your soil if a soil test indicates a PH level below the optimum of 6.0 or 7.0. Soil PH is a measure of soils alkalinity or acidity. A soil is acidic, or “sour”, if it has a PH below 7.0 (neutral).
Soils can be naturally acidic but can also be acidified over time by natural leaching, the use of some nitrogen based fertilizers, excessive rainfall or irrigation, and acidic water sources.
A PH below 6.0 causes important plant growth nutrients to become “bound up” in the soil, making them unavailable to the plant. As a result, the turf can decline including a loss of color, reduced vigor and diminished ability to recover from heat and drought stress.
Is liming necessary? The need to lime will be determined by soil tests. Working towards an ideal PH level will help bring the soil into balance and allow for optimum nutrient uptake.