Coring Golf Greens and Why It's Done

Plugs left behind after coring, part of the aeration process.
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"Coring" is a golf course maintenance term that refers to the process through which putting greens (and sometimes fairways) are aerated. The process of aeration (also known as aerification) is a course maintenance technique that loosens the soil, opens up growing room for turfgrass roots, and helps air, moisture and nutrients get to the roots.

Coring is the way all that is done: A special machine removes small cores (also called plugs) of sod from a green, leaving a hole (and sometimes the removed core) behind. This process is done once, sometimes twice, a year at golf courses.

Coring the greens is also called punching the greens or plugging the greens. Sometimes superintendents will refer to the process as "core aeration," and "coring" might even be used as a synonym for "aeration." (Most golfers think of aeration/aerification as the whole process of coring, topdressing and waiting for the greens to heal.)

The Coring Process

The USGA Greens Section explains some of the various methods for coring greens:

"There are dozens of methods superintendents use to aerate greens, the most popular being half-inch-diameter hollow tines, commonly referred to as conventional coring, but there are also small, pencil-sized hollow tines, high-pressure injection of water and/or sand, large-diameter drills and many others involving tines, knives, or blades of varying shapes and sizes."

It takes a couple weeks for greens to fully heal after being cored, but they will be healthier moving forward. Quoting the USGA Greens Section again:

"Although core aeration temporarily diminishes putting quality, the short-lived pain results in a long-term gain for turf health by reducing thatch and organic matter levels, relieving soil compaction, increasing soil oxygen levels and stimulating healthy growth."

For more, read about the aeration process. There's also a 25-second YouTube clip that provides a close-up look of a hollow-tine machine coring a green.