Too much thatch can smother your lawn, but raking up thatch is a hassle, and dethatchers can damage your grass. Verticutting, or vertical mowing, gives you an easier, gentler way to cut through the thatch to let more water, oxygen, and nutrients reach your lawn’s roots.
Verticutting for a Healthier, Lusher Lawn
Verticutting is a method of breaking up the overgrown plant material known as thatch using a verticutter machine. A verticutter is pushed or steered over the lawn like a lawn mower, but instead of a large blade that cuts the grass horizontally, a verticutter is equipped with a set of small blades that cut down into the turf.
The blades can be set high to break up overgrown stolons and rhizomes, encouraging the grass to put out more leaves and create a denser turf. Setting the blades lower breaks up excess layers of thatch, letting your grass absorb moisture, oxygen, and nutrients and making it less vulnerable to insect damage and disease. Some newer machines pick up any thatch they remove, but most don’t, so you’ll need to do some light raking afterward.
Verticutting helps get rid of weeds naturally. Golf course groundskeepers often use verticutting to control annual meadow grass because the process removes the seed heads that allow the meadow grass to spread.
Because the cuts are so shallow, they don’t reach far enough below the soil to damage the grass’ roots. This makes verticutting ideal for light annual dethatching. It’s also helpful to prepare the lawn for overseeding. The thin, shallow grooves the blades cut into the turf create an ideal seedbed.
Verticutting blades only affect surface organic material, so you’ll still need to aerate and dethatch regularly to keep your lawn’s root zone healthy.
Finding the Right Schedule
If your lawn’s thatch is between 1/2 to 3/4 inch thick, it’s a good candidate for verticutting. For thatch more than an inch thick, you’ll get better results from a more aggressive dethatching tool, such as a power rake or dethatcher.
The ideal time to verticut is fall or late summer when the lawn is still actively growing. Spring is the second-best time. Avoid verticutting when the lawn is under stress from heat, drought, or cold because the added stress of verticutting leaves the lawn temporarily more vulnerable to disease. Don’t verticut when your lawn is suffering from a fungal disease or other infection. The process can spread the infection to the whole lawn.
Slow-growing grasses, such as tall fescue, zoysia, and perennial ryegrass, produce little thatch, so verticutting once a year is enough. Fast growers, such as St. Augustine, Kentucky bluegrass, creeping red fescue, and creeping bentgrass produce a lot of thatch and can benefit from two or three verticuttings a year.
Finding the right schedule for your lawn is a matter of trial and error. Pay attention to your lawn’s health and note when it seems to be benefiting, then verticut more or less often as needed.
Getting Started with Verticutting
Try to avoid fertilizing the lawn for around 45 days before verticutting. Any sooner than this, and much of the fertilizer will still be sitting on the lawn’s surface, adding bulk the verticutter has to cut through.
If the lawn needs mowing, mow on a low setting and use a bag attachment or rake up the grass clippings. If your grass is matted down, consider verticutting before mowing. This will get the grass standing upright, making it easier to mow evenly. Soft, damp thatch is easier to cut, so water the lawn several days before you start work or prepare to do the work a few days after it rains.
Before you start, choose settings for your verticutter’s blades. If your model lets you adjust the distance between the blades, choose a setting of around 1 inch apart for thick turf, such as zoysia and Kentucky bluegrass, and around three inches apart for less dense species.
Next, choose a cutting depth. It takes some experimenting to find the right depth for your lawn, but starting with 1/16 inch ensures you won’t dig up the soil on your first try. If that depth doesn’t do much to the thatch, try 1/8 inch or 1/4 inch. Generally, shorter grass requires a deeper cut, but 1/2 inch is as deep as you’ll ever need to go in the majority of cases.
Using a verticutter is much like using a lawn mower. Start on one side of your lawn and steer the verticutter straight over to the next. Then turn around, move over to start a new strip, and steer back to the other side. Once you’ve covered the whole lawn this way, go over the lawn again, creating strips at a 90-degree angle to the first strips. If your first strips run north to south, the second ones should run east to west.
When you’re done, rake up the thatch removed to prevent it from being compacted back into the soil. If your lawn is due for fertilizing, after verticutting is a good time to do it. Fertilizing at this point also helps the lawn recover faster.
Verticutting is a relatively gentle way to cut through thick thatch that can block water and nutrients, but it’s still something to approach with care. On your first run, start with a shallow blade depth to see how it affects your thatch. The first year, verticut no more than twice and pay close attention to your lawn’s condition afterward.