All About Thatch: Why, How, and When to Dethatch a Lawn

Randy Fath, Upsplash.


With more time spent homebound these days, many folks are bringing their laptops outside, turning their gardens and yards into outdoor offices. An uneven, spotty and not-so-green lawn isn’t such a pretty sight but this forced time at home presents the perfect opportunity for freshening up the garden and assessing the health of the lawn.

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Landscaping experts from YardSmart offer some tips on how to restore your lawn—even a small patch– to one that’s healthy, lush and green.

Daniella Shams, Upsplash.

Remove Thatch From the Soil Surface
All grasses have lifespans determined by their species. At some point they develop thatch, a naturally occurring layer of living and dead organic matter that lies between the lawn surface and the root system and soil below. A matted combination of stems, stolons, rhizomes and roots, thatch does not decompose as fast as it forms.

While a thin layer of thatch, less than 1/2-inch, is beneficial, a thicker layer poses problems. A small amount functions like organic mulch by keeping soil moist and reducing temperature fluctuations. It enables water, nutrients and air to penetrate the soil and reach the roots. But when the thatch layer becomes thick, the grass suffers.

As the thatch builds up, it creates an impenetrable layer that deprives grasses of oxygen, makes it difficult for nutrients to reach the soil and can cause pest problems. Controlling and eliminating thatch is a process known as “dethatching” and here’s how it works:

• Begin by choosing grasses that aren’t high thatch-producing species
• Dethatch the lawn using power rakes or vertical blade lawnmowers
• Frequently monitor the soil to determine nutrient, soil pH, and acidity levels
• Avoid the use of pesticides and chemical fertilizers

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Aerate The Lawn
Healthy lawns have sufficient microbial activity aided by proper soil aeration. Repeated foot traffic may cause the grass to become compacted, reducing soil aeration under the surface. The resulting soil structure will have be damaged with less circulation, water drainage, nutrient absorption, and microbial growth– all of which are essential for healthy grass growth.

Fixing compact soils requires a process known as core aeration. A manual or machine powered core aerator punches holes in the lawn about three inches deep at four-inch intervals throughout the lawn. Core aeration can facilitate greener grass growth in the following ways:

• Loosens the structure of compacted soils
• Increases air movement through the soil
• Increases microbial activity
• Facilitates the breakdown of thatch into manure

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Water The Lawn Properly
Although most people understand that water is non-negotiable in lawn care, they too often rely on rainwater to do the job. As that isn’t a sufficient method for irrigating lawns in dry climates during the summer, or in areas with little rain, many people invest in an automated irrigation system.

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The effectiveness of the watering system depends on how it’s used. Turning on the sprinkler infrequently and for a few minutes won’t produce the desired result. Plants need to be watered deeply and consistently with up to 1 inch of water. The perfect time to water the lawn is in the morning and evening when the sun is not up.

Automated irrigation systems can help to owners achieve better watering results. These systems can be programmed to water at a specific time of day with the desired amount of water. Automating the process can save water and therefore money.

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Fertilize and Compost
Fertilizers can be great for improving the color of the lawn however be cautious when it comes to their application. There are two types of fertilizers: organic and chemical. Aim to steer clear of toxic chemicals, and if you feel you need to fertilize, instead choose healthier organic fertilizers and compost that are better for the lawn and don’t leach toxic chemicals from the soil into groundwater.

Chemical fertilizers may make the lawn look healthy on the surface, but that deceives the eye. They strip the soil of needed nutrients including desirable microbes and earthworms and also make the grass more susceptible to disease and pests. In addition to reducing chemical exposure, organic treatments will revitalize the lawn’s ecosystem as they break down slow thereby increasing the soil’s ability to hold water and nutrients.

Consider too making your own compost from recycled organic kitchen waste to make nutrient-rich, organic soil. You can apply a thin layer of compost, known as “topdressing”–typically one-quarter to one-half inch thick–in spring or fall, depending on the local climate and soil. Adding a thin layer of compost will help improve aeration, naturally raise moisture in the the soil and and help reduce weeds.

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Mow The Lawn Correctly
Most people understand the need to mow their lawns, but only a few know how to do it correctly. What determines whether a lawn is mown correctly include the following:

Use the Right Mowing Equipment
A mulching mower is ideal for mowing lawn grass. It works like other mowers, but has an additional blade that cuts grass clippings small so they can fall to the soil beneath the grass.

When a mulching mower is unavailable, use a sharp and well-adjusted mower that can cut the grass crisply rather than tearing it off at the roots. Mowing this way can prevent diseases and keep the grass looking green after it’s cut.

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Control Mowing Height
The mowing height of grass should not be more than 3.75 inches tall in order to prevent scalping. Also, taller grass is more resistant to the action of the mower.

Determine How Short to Cut Grass
How short to cut grass depends on the season and the type of grass. Ideally, the amount of cut grass should not be more than a third of the grass’s ideal height. This allows the grass to keep protecting the soil beneath it from the sun’s harsh heat and limits weed growth with its leaf cover. Regulating the cut height is practical as leaving grass clippings for mulching also means there is less to cart away.

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Seasonal Cutting Heights
In spring, mow cool season grasses to a maximum height of 3+ inches, and warm season grasses as low as half an inch and up to 1.5 inches. Summer: In summer, mow cool season grass to 3 or 3.5 inches or up to 4 inches for tall fescue and perennial ryegrass. Cut warm season grasses to about 2 to 2.5 inches. Inching into fall, mid-length grass is the preference. Winter: In winter, tall grass may become matted and prone to disease, but when cut too short, the roots can become exposed and damaged by very cold temperatures. Fall: In fall, aim to strike a good balance when mowing in fall to prepare the lawn for winter. Cut cool season grasses to roughly 2.5 inches before the first winter frost, and warm-season grasses to 1.5 or 2 inches.

Mowing Frequency
How often to mow the lawn depends on the season. In early summer and spring it’s generally a good idea to mow weekly or biweekly and in winter to up to 4 weeks.

Rob Sheahan, Unsplash.

Stick to a Routine
To achieve optimal results and maintain a healthy, lush green lawn, create a lawn care routine:

1. Remove thatch from the grass
2. Aerate and water properly
3. Fertilize appropriately
4. Mow properly according to the season and type of grass

Rumman Amin, Upsplash.

With proper routine care, your lawn will be greener, provide improved curb appeal, and also create a more inviting and aesthetically pleasing backyard, garden space–or outdoor office.




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