De-thatching and Power Raking

Overview

Thatch is a layer of grass stems, roots, clippings, and debris that settle on the surface of your lawn’s soil and either slowly decompose and/or accumulate over time. A thin layer of thatch is natural and a positive thing. It keeps a lawn healthy by insulating against temperature extremes, slowing water loss, and curbing the growth of weeds. It also forms a layer of cushion that helps your lawn tolerate foot traffic. But your lawn can accumulate too much thatch, which can weaken the health of your turfgrass. First of all, too much thatch blocks the lawn’s roots from growing as deeply as they should. When grass roots spread in the thatch layer – rather than the soil below – the lawn is vulnerable to drying out. A thick thatch layer also prevents water and nutrients from getting to the roots that are deeper in the soil. Thatch can even promote disease by holding in too much moisture and harboring harmful insects.

A thatch build-up problem is not an automatic consequence of a healthy, consistently growing lawn. Applying compost and other organic fertilizers stimulates biological activity that controls thatch development. Healthy soils also host and generate large populations of micro-organisms that consume thatch as fast as it is created. However, certain types of turfgrass species popular in Canada such as Kentucky bluegrass are more prone to thatch development. For this reason, your thatch layer should be examined every year to determine if de-thatching should be performed. When the thickness of your thatch layer exceeds ¾ of an inch, your lawn has too much thatch. In many cases de-thatching can be required once per year.

The good news is that there is mechanical equipment available on the market for purchase or for hire to help homeowners eliminate excess thatch – hours of raking, followed by blisters and sore shoulders, is not the only solution! The rotating blades of a mechanical de-thatching machine (also known as a “Power Rake”) can quickly and thoroughly take care of your thatch problem and all that is left to do is to rake up and bag the unwanted fluffy thatch. Homeowners using a mechanical de-thatching machine for the first time should not be worried by the distressed look of their lawn. A thorough removal of thatch will leave your turf looking beat-up but it will soon recover.

In Canada’s Wet (West) Coast, excessive moss proliferation is a common lawn-based problem. The high amount of precipitation acidifies the soil, which unfortunately creates the ideal growing condition for moss. If left unchecked, the moss can take over – potentially choking out your turfgrass altogether. In addition to neutralizing the acidic condition of your soil by applying lime multiple times per year (we recommend the Dolopril lime formulation due to its ease of application), a de-thatching machine offers a very effective way to remove the moss from your lawn so that the grass can re-establish itself. However, please note that it’s very important that you repeatedly apply the lime if your lawn soil remains acidic otherwise the moss will surely make its return.

Why is De-Thatching or Power Raking Performed?

Simply put, de-thatching is a recommended lawn care service for the numerous direct and indirect benefits both to your lawn’s health but also the health of the ecology and your household budget!

Reduces/Eliminates Thatch Barrier

Thatch is a layer of grass stems, roots, clippings, and debris that settle on the surface of your lawn’s soil and either slowly decompose and/or accumulate over time. A thin layer of thatch is natural and a positive thing. However, a thick thatch barrier can deprive your soil (and ultimately your lawn’s root system) of rain water, oxygen, and nutrients. De-thatching (or power raking) is the #1 way to eliminate the problem of excessive thatch build-up.

Increases Oxygen Content in the Soil

In addition to requiring nutrients and moisture, your lawn’s root system needs to breathe. Adequate oxygen content in the soil is vital for root development but this can be compromised by a thatch barrier that is too thick and dense. The elimination of excessive thatch by performing a de-thatching enables increased oxygen to reach the soil, then the root system and ultimately contributes to the health of your turfgrass.

Improves Fertilizer Uptake

Spreading fertilizer on a lawn with a thick thatch barrier is a surefire way to get poor uptake and minimal benefit from your fertilizer. The unsatisfactory results are compounded when the fertilizer is applied on windy days since the granular fertilizer is more likely to be blown away or during heavy rainfall when the fertilizer is likely to be carried away in the run-off water (due to the thickly thatched base of the lawn being unable to absorb the rain). Not only get maximum fertilizer results – but also maximum return on investment – by de-thatching before fertilizing since this will ensure that the majority of your fertilizer reaches its target: the soil base.

Increases Water Uptake

Lawns with excessive thatch build-up become hydrophobic! These lawns repel water no matter how much you water them. A de-thatching will expose the surface of your lawn’s base allowing water to soak into the soil, reaching your lawn’s root system. Not only will this spur new turfgrass growth, your watering efforts will not be in vain and you might save money in the process!

Improves Germination Results of Over-Seeding

As we have learned of the hazards of fertilizing a thickly thatched lawn, the same principle applies to applying new grass seed (i.e., over-seeding). High quality grass seed is not cheap so homeowners should be aware that strong winds and heavy rainfall could interefer with their over-seeding efforts. Another concern is birds and rodents, since they love the taste of freshly scattered grass seed. De-thatching the lawn prior to over-seeding helps address these concerns by increasing the contact of the seed with soil, where it can commence germination. Reducing the thatch also boosts the chances of successful germination since the young seedlings have less thatch to battle against as they develop and sprout. For these reasons, we highly recommend pairing de-thatching with over-seeding.

Spurs New Turf Growth

A steady introduction of healthy, new lawn shoots each year will keep your lawn vibrant and resistant to harmful weeds and insects. However, these new lawn shoots require room to grow. When turfgrass and the underlying soil has improved access to water, oxygen, and nutrients – coupled with the clean slate created on the surface of the lawn by the de-thatching process – all the necessary ingredients are in place for the magic of new turf growth. For this reason, de-thatching reminds us of the idiom “out with the old and in with the new”!

Improves Soil Drainage and Reduces Runoff

Lawns with a dense thatch barrier suffer from water pooling and soggy lawns when the snow melts or after heavy rainfall. Sloping properties additionally suffer from water runoff preventing rainfall and sprinkler water from adequately reaching the base of the soil. A thorough de-thatching will improve your property’s soil drainage and can resolve the problem of water runoff.

Helps Reduce Need for Weed Control

Weeds establish and thrive in weaker, thinner, and less-managed turfgrass.  Although de-thatching does not directly kill weeds, it does help in preventing their arrival and survival by promoting a thick, healthy turf environment that is not ideal for weed development.

Helps Reduce Need for Insect Control

Insects tend to all prey on – and gain victory over – thin, sparse lawns. Many inspect species also prefer to lay their eggs in damp, thatch-filled lawns. While de-thatching does not directly kill insects, it does make a lawn less inviting by creating an inhospitable breeding ground and, by promoting a thicker, healthier turfgrass, roving insects will move on to look for easier turf to infest.

Eliminates Moss Naturally Without Reliance on Chemicals (British Columbia)

In much of the Lower Mainland of British Columbia and Vancouver Island, homeowners seem engaged in a never-ending battle against moss overtaking their turfgrass as the dominant ground cover vegetation in their yards. Fortunately homeowners can turn to a mighty tool in the battle against moss: the power rake. This machine masterfully removes truckloads of unwanted moss from afflicted lawns while preserving the turfgrass in the process.

Frequently asked questions

• What is the difference between de-thatching and power raking?

  It depends who you ask. The equipment used for both services is the same so the only difference for some lawn care professionals and service providers is in how they use the equipment. Specifically, some refer to a “power raking” as a service where the de-thatching machine’s blades are set fairly shallow, bringing up only a moderate quantity of thatch and/or moss. A “de-thatching” is a more intense service where the blades are set to cut into and through the entire thatch layer resulting in the maximum removal of thatch and/or moss. The difference on a thickly thatched or heavily moss-infested lawn can be as dramatic as a few bags of raked up thatch versus dozens of bags of thatch or moss removed from your lawn. Canadian Property Stars only uses the de-thatching machine as it was intended to be used, i.e., to deploy the power of motorized equipment to do what human power cannot – fully remove the excess thatch from your lawn without back-breaking effort. In our view, a shallow “power rake” only serves the interests of commercial lawn care companies and not those of homeowners.

• What time of year should I de-thatch/power rake my lawn?

  Mid to late spring is the best time of year to de-thatch since your lawn has had time to dry out after the wet early spring and the turf has begun to re-establish itself. De-thatching too early in the spring or in the hot, dry summer adds unnecessary stress to your lawn. The other reason it is ideal to de-thatch in mid to late spring is that you can time the de-thatching service to be performed in conjunction with aeration, over-seeding, and fertilization (as well as lime in British Colombia) for an overall lawn rejuvenation package. This is a unique on-demand full lawn care treatment offered exclusively by Canadian Property Stars.

• Does every lawn require de-thatching?

  Most lawns – if checked – could benefit from a dethatching especially those in Eastern and Central Canada where Kentucky Bluegrass is commonly used to seed lawns or the West Coast of Canada where moss is an issue. However, it’s important to remember that thatch is not the enemy – excessive thatch is. In fact, a thin layer of thatch is natural and a positive feature that keeps a lawn healthy by insulating against temperature extremes, slowing water loss, and curbing the growth of weeds.

• What are the steps involved in a professional de-thatching service?

  After setting the de-thatching machine’s blades to the appropriate setting to pull up only thatch and not the grass from its roots (a test strip should always be performed to verify), the de-thatching service is performed in 2 main steps. First, the self-propelled motorized de-thatching machine is guided over the entire surface of the lawn. As the technician moves along, they leave behind fluffy trails of thatch and/or moss. The second step, once the entire lawn has been de-thatched, is to use a large fan rake to rake up the thatch into yard waste bags. Some lawn care providers even use a specialized lawn vacuum to collect the thatch. Either way, the thatch must be bagged up for removal. Ideally, the yard waste bags will be placed in the garage or under some sort of shelter so that they are not soaked in the rain while waiting for garbage pick-up day. The bags should not be left on the lawn as they will harm the turf if left for too long.

• Does de-thatching damage my lawn?

  It may appear so in the short term but de-thatching will not damage your lawn as long as the machine’s blades are not set so deep that they cut into the lawn’s root system. Yes, some healthy grass will be damaged in the process of de-thatching your lawn but the overall effect will be positive and healthy. It’s similar to the biological phenomenon known as hormesis whereby a beneficial effect (improved health, stress tolerance, growth or longevity) results from exposure to low doses of an agent that is otherwise toxic or lethal when given at higher doses. Very much like weight-training where your body responds to the micro-damage to your muscle fibres by stimulating repair and new growth in your muscle tissue.

• Can I de-thatch in the rain or when the grass is wet?

  De-thatching can be performed in the rain but it is more work for the technician, especially during the raking and bagging stage since the wet, soggy thatch is quite a bit heavier. As long as the machine is not tearing at the roots of the grass, there is no negative impact on the lawn. However, if the choice is between a dry, dusty lawn and a moist lawn after a rainfall, we would choose the moist lawn to de-thatch every time.

• Do I need to rake up the loose thatch once it is brought to the surface?

  Yes, raking up the loose thatch is essential and it is by far the most laborious aspect of the service – assuming you used a proper de-thatching machine to pull up the thatch. Unlike aeration cores that should be left on the surface of the lawn, excessive thatch is meant to lifted out and then removed from the lawn. It’s not a concern if a small percentage of the thatch is not raked up and bagged but the idea is that the majority of it will be gone for good.