Sand topdressing has been a critical practice to produce smooth, healthy putting greens dating back to the early days of golf. In addition to smoothing the surface, sand topdressing helps to dilute thatch and organic matter to keep air and water moving through the soil profile.
Here are some basic principles to keep in mind regarding sand topdressing as well as some new research information to streamline the process.
Topdress with the same sand used to construct the greensLayering is the enemy of putting green turf. Whether it’s layers of thatch or layers of different sand, the layers restrict root growth and water movement through the soil profile. Topdressing the greens with the same sand used for constructing the greens eliminates the chance of layering and promotes a uniform soil profile and a deep, healthy root system.
Periodically test the sand to ensure uniformityMany assume that the sand they get from their supplier will always be the same. Maybe that’s true if your supplier is mining the sand from a single huge deposit, but what if they change locations and start pulling sand from a different part of the pit? To ensure uniformity, it is prudent to perform a sieve analysis of your topdressing sand at one- to two-year intervals.
Match the rate and frequency of sand topdressing to the growth rate of the grassA basic guideline is to apply 100 to 200 pounds of sand per 1,000 square feet every one to two weeks during the active growing season. While this is a broad recommendation, it can be refined and adjusted by measuring grass clippings from a few indicator greens. Take a 5-gallon plastic bucket and place marks on the inside at 1-inch increments and dump the clippings from a single green and record the amount collected. Do this for a couple of representative greens each day (e.g., greens No. 1 and No. 10), and it will be easy to track if the greens are growing a little faster or a little slower and if sand topdressing rates need to be adjusted.
New Research on Light Topdressing Greens
Although sand is great for grass, it is damaging to mowing equipment. A study funded by the United States Golf Association (USGA) at Rutgers University examined the effect of using a fine texture topdressing to see if repeated use would negatively impact soil physical properties. The results from the first two years of the study are very encouraging and can be found in this article, Benefits of Light and Frequent Topdressing, on the USGA website.
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