Your golf course superintendent slices into every putting green you’ve ever put it on. Not once on a sketch, sometimes weekly, always with blades that drop below the surface and cut straight down into the canopy in a way no mower ever does. What you see is destruction, brown stripes across an otherwise perfect green, debris piled on the surface, sand worked into grooves that look like scars. If you’ve walked up to a freshly verticut green, you’ve asked the same question.
Why is my course doing this to me? The answer is the most precise piece of engineering on the property, >> [music] >> and the green plays better the next day. Every championship green you’ve ever put it on owes its roll to this. The grass obeys the blade for reasons that have nothing to do with mowing.
A verticutter isn’t a mower. A real mower spins horizontally and slices grass tips against a stationary bedknife above the soil. A verticutter does the opposite. It holds a row of thin, tightly spaced vertical blades that rotate down into the turf.
The blade tips drop below the surface plane of the turf and [music] cut straight down into the canopy. On a putting green, those blades sit anywhere from 1/64 of an inch to 1/8 of an inch below the height of cut. That’s not a typo. Aggressive [music] verticuts go deeper still.
Bear Trace at Harrison Bay runs champion ultradwarf Bermuda greens with blades dropped 1/8 of an inch below the surface itself. The brown stripes you see are the cut path. The piles of debris are stolons that have been severed and lifted out of the canopy. The equipment makes the difference.
Some Toro Reelmaster verticutter cassettes run blade spacing of 1/8 of an inch. >> [music] >> A Graden walk-behind verticutter carries 2 mm tungsten carbide blade tips at 25 mm space powered by a 13 horsepower Honda engine. Working depth from 0 to 40 mm. CCs makes a verticutter blade 2 mm wide and 240 mm long, carbide [music] tipped for durability against thatch. The United States Golf Association publishes one rule of thumb that governs all of it.
Blade depth should never exceed blade spacing. A blade dropped deeper than the gap between blades destabilizes the turf canopy and risks >> [music] >> thinning the stand. Stay inside that ratio and the green recovers in 24 to 48 hours. Break it and you’ve wounded the green into a thinning stand that takes [music] weeks to fill in.
A real mower cuts above the soil. A verticutter cuts into it. You’ve already watched what this channel covers about aeration on these greens. Holes pulled out by the thousand.
Verticutting is the cut that lives between those holes. Aeration takes a core. Verticutting severs a stolon. [music] Both wound the green on purpose. New videos here every Monday and Thursday cover the rest of the work no one shows you.
Now to the science of why grass obeys a vertical blade. Grass plants want to grow sideways. >> [music] >> Creeping bentgrass and ultradwarf Bermuda grass spread by sending out horizontal stems called [music] stolons that root at every node. Left alone, those stolons form a flat lateral mat of leaves and runners that rolls [music] inconsistent and breaks unpredictably under a putt. None of this is accidental.
The biology rewards horizontal growth. The growing tip of every stolon and every leaf produces a hormone called auxin. Auxin suppresses [music] upright growth. As long as the apical meristem at the tip keeps producing it, lateral buds along the stems stay dormant.
The plant pours its energy into spreading horizontally and never tillers upright from the crown. Sever that stolon and the auxin pathway breaks. >> [music] >> The buds along it wake up. The plant redirects carbohydrate and signaling into upright tillers >> [music] >> from the crown rather than continuing the lateral run. Turfgrass scientists [music] call this apical dominance.
It’s the entire reason verticutting works. You’re not just trimming the canopy. You’re interrupting a hormone gradient >> [music] >> and forcing the plant to grow up instead of out. Then, there’s grain.
Grain is the directional lay of leaf blades and stems on a putting green, the result of all that lateral growth. On greens with heavy grain, the leaves lie flat in one or more dominant directions. [music] Putt with the grain and the ball rolls down a smooth ramp of leaf surface. >> [music] >> Putt against it and the ball runs into the cut ends of every blade in its path. [music] Friction increases. The ball decelerates faster. The break flattens.
The United States Golf Association documented this [music] in the late 20th century. The modern answer was lower mowing heights. Greens that were cut at a fifth of an inch in the 1970s [music] are cut at 1/10 of an inch today. Most of the grain has been physically removed by that height alone.
The residual horizontal mass that the mower cannot reach is [music] what verticutting eliminates. A green with no visible grain reads consistently from any direction. Every break [music] truce. Every speed reads honest.
None of that is natural. Verticutting builds it. Then there’s thatch. Thatch is the layer of partially decomposed stems, [music] crowns, stolons, rhizomes, and roots between the canopy and the soil. >> [music] >> It accumulates whenever the plant produces organic matter faster than soil microbes can break it down.
Heavy nitrogen fertilization speeds it up. So do acidic [music] soils. So do shaded greens with poor air circulation. A highly maintained Kentucky bluegrass turf can lay down a fifth of an inch of thatch every year.
The high shoot density bentgrass cultivars used on tournament greens, varieties like Penn A-4 and Pure Distinction, accumulate it faster still. Once the layer reaches half an inch, the green plays soft and [music] spongy. Water holds in the surface. Ball roll wobbles.
The lignin and stolen and crown tissue resist microbial decomposition. Chemistry won’t erase it. Researchers at the University of Georgia under Dr. Robert Carrow have documented enzyme treatments that slow accumulation.
The conclusion is the same. The only reliable program is mechanical. Verticut to remove the material. Topdress with sand to dilute what remains.
Aerate to give the root zone room to drain. All three on the same calendar every season. That calendar belongs to one person, the golf course superintendent. Not the head pro, not the general manager.
The superintendent owns it. The schedule changes by grass type. On a creeping bentgrass green in the cool season northeast, [music] a maintenance verticut runs every 14 days during the growing season. Light blades set between [music] 1/64 and 1/8 of an inch below the height of cut.
The point is to keep the canopy upright and to give the next sand topdressing a groove to settle into. On an ultradwarf Bermuda grass green in the south, >> [music] >> the cadence accelerates. Champion, MiniVerde, TifEagle, Mach One. Those greens take a light verticut every week through summer because warm season grasses spread [music] that fast.
Skip a week and the lateral growth catches up. Skip two weeks and the surface goes spongy. Two or three times a season the superintendent calls for an aggressive pass. Deeper blades, slower travel speed, often paired with hollow core aeration in the same week.
Bear Trace at Harrison Bay runs the program in summer, blades dropped 1/8 of an inch below the surface, a two-direction backtrack pattern. Greens recovered in roughly four days. Tournament prep is its own program. The last aggressive verticut runs three to four weeks before the event.
Beyond that point, only light grooming. On a non-overseeded ultradwarf in the desert southwest, the last hard pass finishes in late August. By championship season in October, the surface has healed and the grain is gone. This is a schedule that runs underneath every championship round you’ve ever watched.
Augusta National maintains its own version. So does every host of the United States Open. So does every PGA Tour stop. So does every weekend members club that produces a green you remember rolling true.
None of it is improvisation. It’s one or two superintendents, a calendar, and a verticutter. Every green you’ve ever put it on lives in the schedule. Some courses run it tighter, some run it looser.
The municipal track you played last Saturday verticuts on a 14-day cycle even if the crew never tells the players. The high-end private club that hosts the United States Open sectional qualifier verticuts on a weekly cadence. The blades are carbide tipped. [music] The members never see them touch the surface. The reason your putt rolled true the last time you stood over a 12-foot par saver wasn’t the grass.
It was an accumulation of hundreds of vertical incisions across the growing season. The sand topdressing brushed into the grooves those incisions opened. The superintendent reading the organic matter accumulation rate of the greens and deciding when to cut and when to wait. You’ve never seen this work.
You’ve only seen the brown stripes the morning the crew finished a pass. By Tuesday afternoon, those stripes [music] are gone. By Wednesday morning, the green plays faster than it did before. The schedule continues.
This channel covers the work your superintendent’s doing while you’re not on the course. The chemistry, the decisions, the schedule, the mechanics. If [music] that’s the side of your course you want to know about, subscribe. New videos here every Monday and Thursday.
If you want to know what makes a real mower cut a sheet of paper without tearing it, watch the backlapping video next. We’ll put it on the screen for you. You’ll see why the same superintendent who runs this verticut program [music] tests every reel mower blade with a single sheet of paper held in the air. He does it before the blade ever touches the green.
The blade has to slice. If it [music] tears, the green pays for it. Now you know what they do before you tee off. >> Mhm.