Golf Tutorials

What Is Coring Golf Greens?

By Spencer Lanoue
July 24, 2025

Showing up to your favorite course only to find the putting greens covered in tiny holes and a layer of sand can be one of the most frustrating sights for a golfer. This article will explain exactly what coring is, why this temporary disruption is VITAL for the long-term health of the greens, and how you can adjust your game to play your best on them.

What is Golf Green Coring, Exactly?

At its core (no pun intended), coring - also known as core aeration or aeration - is a mechanical maintenance practice that involves punching holes into the green's surface and pulling out small plugs, or "cores," of turf and soil. If you've ever heard someone say the greens have been "punched," this is what they're talking about.

Imagine a machine that looks a bit like a large lawnmower, but instead of spinning blades, it has rows of hollow metal tubes called "tines." As this machine moves across the green, these tines punch down into the ground, typically a few inches deep, and extract small cylinders of soil and grass. These cores are then usually left on the surface to be cleaned up later.

After the cores are removed, groundskeepers will typically follow up with a process called "topdressing," which means spreading a thin layer of sand over the entire green. This sand has a twofold purpose: it helps smooth out the surface and, more importantly, it fills the holes left by the coring machine. This helps improve the soil structure over time.

While an inconvenience, this process is arguably the most important procedure a golf course superintendent performs all year. It's the difference between greens that are firm, fast, and healthy, and those that are spongy, diseased, and inconsistent.

The ‘Why’ Behind the Holes: 4 Big Reasons for Coring Greens

So, why would any superintendent deliberately "injure" the most important part of the golf course? It all comes down to creating a healthy environment for the grass to thrive. Healthy grass requires healthy roots, and healthy roots need air, water, and room to grow. Coring helps with all of these things.

1. Reducing Soil Compaction

Think about what a putting green endures every single day: hundreds of golfers walking across it, heavy mowing machinery rolling over it, and the constant pressure of feet and equipment. Over time, this intense traffic squishes the soil particles together, a process called compaction.

When soil becomes compacted, the tiny air pockets that naturally exist between soil particles are squeezed out. This creates a hard, dense layer that roots can't penetrate. Water has a hard time soaking in, often just running off the surface instead of getting down to the root zone where it's needed. By poking millions of holes in the ground, coring physically breaks up this compaction, creating new channels for air and water to a reach depths they couldn’t get to on their own.

2. Removing Harmful Thatch

Thatch is a layer of dead and living organic material - like stems, runners, and decomposing leaf tissue - that builds up between the base of the grass blades and the soil surface. A little bit of thatch is fine, but when it becomes too thick (typically over half an inch), it acts like a thick, water-logged sponge.

This spongy layer causes all sorts of problems:

  • It holds too much moisture at the surface, which creates a perfect breeding ground for fungal diseases.
  • It prevents water, air, and fertilizers from reaching the soil and the roots.
  • It creates a soft, inconsistent putting surface where shots don't bounce predictably and footprints leave deep indentations.

Coring a green is the most effective way to physically remove this problematic thatch layer. Pulling up thousands of cores directly removes the build-up and introduces sand into the profile to create a firmer, healthier surface.

3. Encouraging Deeper Root Growth

Just like any plant, turfgrass needs strong, deep roots to be healthy and resilient. Deep roots allow the plant to draw water and nutrients from further down in the soil, making it much more tolerant to stress from heat, drought, traffic, and disease.

However, in compacted, thatch-filled soil, roots have nowhere to go. They tend to stay shallow, making the plant weak and susceptible to problems. Coring creates new pathways in the soil. With the hardpan broken up and channels of fresh air available, roots are encouraged to grow deeper into the soil profile. This is the foundation of creating a turf that can withstand the demands of a busy golf season.

4. Improving Air & Water Exchange

Healthy soil is like a breathing organism. It needs to "inhale" oxygen and "exhale" carbon dioxide. When soil gets compacted, this gas exchange cycle breaks down. Without oxygen, beneficial microbes in the soil die off, and the roots essentially begin to suffocate.

Aeration holes are direct pipelines for oxygen to get deep into the root zone. They also act as drainage channels, allowing excess surface water from rain or irrigation to move down through the soil profile more quickly, preventing soggy, water-logged conditions that can cause rot and disease.

Your Guide to Playing on Punched Greens

Understanding why greens are cored is one thing, but figuring out how to play on them is another challenge entirely. The ball will not roll true, and it can be incredibly frustrating. The key is to adjust your strategy and, most importantly, your expectations.

Strategy for Putting

Forget everything you know about finesse putting. On a bumpy, sandy surface, a delicate, dying putt has absolutely no chance. The ball will be knocked offline by the first hole or sand particle it encounters. Your goal is to be aggressive.

  • Think speed, not line. The line you read is only a suggestion. Your number one priority is a firm, solid strike. Hit the ball with enough pace that it holds its line as much as possible and isn't as affected by the bumps. A good rule of thumb is to imagine the cup is 18 inches farther away than it actually is.
  • Play less break. Since you're hitting the ball firmer, it will have less time to be affected by the slope of the green. Cut the amount of break you read in half and trust the pace.
  • Use a "pop" stroke. Avoid a long, flowing putting stroke. A shorter, more concise, "popping" motion can help you hit the ball more squarely and give it a better initial roll, getting it on top of the sand as quickly as possible. Take any forward press out of your stroke and try to hit the absolute equator of ball.

Strategy for Chipping and Pitching

That sandy, porous surface will also significantly impact how your ball reacts around the green. The ball will land much softer and have very little release compared to a normal, firm green.

  • The ball won't roll out. A shot that would normally run out 10-15 feet might only roll out a couple of feet, if that. You need to adjust your landing spot. Plan on flying the ball closer to the hole than you typically would, especially on pitches and longer chips.
  • Consider the bump-and-run. For shorter shots around the fringe, a low bump-and-run with an 8-iron or 9-iron can be a very effective play. It gets the ball down on the ground and rolling like a putt right away. While it will still be bumpy, this approach is often more predictable than trying to fly a softer wedge shot into a messy surface.

The All-Important Mental Game

This is arguably the most important tip. You must accept that you're going to miss some putts that you would normally make. Your playing partners will too. Do not let it ruin your day.

  • Adjust your expectations. If you're playing for a score, just add a mental 2-3 strokes to your target for the day. Simply acknowledge that conditions are tough and go with the flow.
  • Change your focus. Instead of focusing on your score, maybe focus on hitting a certain number of greens in regulation, or just enjoy the process of hitting good tee shots and approaches.
  • Laugh it off. When your perfectly struck 6-foot putt hits a bump and veers 90 degrees offline, just laugh. Getting angry accomplishes nothing. Remember that the pain is temporary, and those beautiful, pure greens are just a couple of weeks away.

Final Thoughts

Coring golf greens is a classic case of short-term pain for long-term gain. While it might impact your round for a week or two, this essential maintenance practice is the single most important thing a superintendent does to guarantee healthy, firm, and enjoyable putting surfaces for the rest of an entire season.

Navigating unusual course conditions like aerated greens often comes down to strategy and confidence. When you're faced with situations that take the guesswork out of the shot, having a reliable caddie is invaluable. For those tough decisions around a punched green - like whether to chip high or putt from the fringe - you might have questions about the right approach. With Caddie AI, we made it so that you can get instant, expert advice right on your phone, helping you adapt your strategy to any course condition and play your most confident golf.

Spencer has been playing golf since he was a kid and has spent a lifetime chasing improvement. With over a decade of experience building successful tech products, he combined his love for golf and startups to create Caddie AI - the world's best AI golf app. Giving everyone an expert level coach in your pocket, available 24/7. His mission is simple: make world-class golf advice accessible to everyone, anytime.

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