It's that's time of year to evaluate the needs of the soil under our playing surfaces. For tees, fairways and approaches, we use Harris Labs in Lincoln, Nebraska to do our soil testing. For greens rootzone testing, I use a lab in Pittsburgh, PA. Harris Labs does a nice job with a quick turn around time. There are a number of things I'm looking for in a soil test. The main thing is soil pH. If our pH is too low (meaning the soil is acidic), it may require a calcitic lime application in late fall-early winter. The lime reaction takes months to occur so the sooner lime is applied, the better. The reasons soil pH is important is the effect it has on nutrient availability to the turf. A soil pH range of 6-7 is ideal. When the soil pH is too low or too high (acidic or basic) there are a number of nutrients the grass needs that become unavailable. We can raise soil pH by using lime and calcium products. When soil pH is high (7 or more) sulfur based products like ammioum sulfate are effective in lowering soil pH.
These soil test results may also indicate the need for a particular nutrient application immediately or simply to guide me in the decision making process of which fertilizer to select come spring. At HCC, I will usually select 4 Fairways, 4 tee boxes and 4 approaches to select soil samples from. I feel these 12 samples give me a good representative sample of the golf course and allow me to make an accurate judgement on fertilizer needs and purchases. Greens however, are tested 2-3 times annually. While this might be overboard for some, a sand based rootzone under a USGA green fluctuates more than a native soil fairway. Excessive rainfall can deplete nutrients in the sand. In a golf green, inputs are required more regularly and I enjoy seeing how the soil test results compare to the visual characteristics of the turf. Tissue testing is also an important component of greens management. Grass clippings can be analyzed to tell you exactly what nutrients are inside the leaf blade and whether or not the grass has what it needs for optimum health.