How to Power Rake or Dethatch Your Lawn

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Sometimes you have to be cruel to be kind, right? So, even though the thought of slicing and ripping and tearing into your lawn might stick in your craw, it’s often an essential maintenance exercise. Read on to get the lowdown on how to power rake or dethatch your lawn.

It’s often the things that happen out of sight that prevent your lawn from showing at its best. Thatch is one of the big culprits.

We’re going to tell you what it is, how it builds up in your lawn, how to get rid of it, and above all, how to make sure it doesn’t return. If you want to learn more about power raking itself, we talk about this more in this article.

What is thatch?

Here’s a simple exercise you can do yourself. Grab a gardening trowel or a spade, and lift a section of your lawn, roots and all. Like a slice of pie.

Have a look at the earth and the root system that came up with the grass. See that layer of dead and slightly-living grass that’s all intermingled. It’s the bit above the soil and below the green grass leaves.

That’s thatch.

Not all thatch is bad. A bit of it is good.

  • It makes the grass feel good under your feet – a bit like a natural carpet
  • Thatch protects the grass against excessive wear in high traffic areas
  • It insulates the soil where the temperatures are extreme

Thatch build-up is strongly dependent on the kind of grass you have. Some are completely resistant to thatch – and these strains need virtually no dethatching. But with other strains, the thatch accumulates quickly and power raking or dethatching becomes a yearly chore.

In short, thatch forms when organic matter in grass develops quickly and decomposes slowly.

The problems associated with thatch

It’s great if your grass feels lush underfoot, but when the thatch is allowed to build up excessively, it can lead to:

  • Excessive humidity – this promotes all kinds of diseases
  • Rapid growth and spread of insects and fungi
  • Limited circulation of nutrients, water, and air – these limit healthy root growth

For a while thatch was blamed on accumulated lawn clippings, but they’re actually not the culprit. Dead leaves, stolons, rhizomes, and all kinds of other micro and macro vegetation should shoulder the blame.

Unhealthy lawn with spots

What actually causes thatch then?

  1. If your friend the earthworm has moved away, you’ll see an increase in thatch. The earthworms oxygenate the soil and they also contribute HUGELY to the breakdown of organic material in general.
  2. If your pH levels are out – especially if the soil is too acid, thatch can become problematic. The microorganisms that are usually your first line of defense against thatch need a pH of somewhere between 6 and 8. (A bit of added lime can solve this problem!)
  3. If you add a lot of nitrogen throughout the year, it stimulates the growth of all kinds of things – not only grass. The natural processes that break down the dead material can’t keep up with the vigorous growth, and the result is thatch.
  4. Insufficient aeration. As roots grow thicker and longer, and they need space. If your soil is too compacted, it will inhibit root growth, and that will lead to excessive thatch.

Kentucky bluegrass is great when it’s music, but not so much when it’s grass. This variant grows long and thick stems underground, and these take a long time to break down.

Once the thatch layer is thicker than an inch it starts to cause a whole host of problems.

How do I know my lawn needs a power rake or a dethatch?

The easiest way is to take a garden trowel or a spade and lift out a slice of your lawn – about the size of a decent slice of pie. If you see more than an inch of dead and dry plant material between the green top and the earth-and-roots, it’s time…

If this is the case, your lawn will probably show other signs too:

  • Footprints when you walk across it
  • Dry spots
  • More insects than usual
  • Less resilience. It will show that it’s in distress when it’s cold, for example
  • And increase in lawn diseases

If this is the case – HANG BACK! I know this is counterintuitive, but wait until the lawn is healthy before you power rake or dethatch.

When should I dethatch then?

The actual time of year is largely dependent on the strain of grass you have. Cool-season lawns and warm-season lawns have completely different growth patterns. Either way, you should only dethatch when they’re in an active growth phase.

For cool-season grasses (Kentucky bluegrass is one – the lawn, not the music), dethatch in or around spring. Even late summer or early fall if the signs tell you dethatching is necessary.

Warm-season grass – these are strains like St. Augustine and Bermuda and their variants – dethatch in summer when they’re growing at their most vigorously.

A traditional rake lying on grass

The preparation

Remember, your lawn is going to need a recovery period after a power rake. So make sure the conditions are ideal for the most rapid recovery possible to prevent lasting damage. Your grass will need at least four weeks of good growth time for proper recovery before the season turns.

Always make sure the soil is moist. NOT wet, though. If you water your lawn properly around two days before you do the power rake, that should suffice.

Do at least three passes with the power rake or dethatcher over your ENTIRE lawn. And change the direction every time for the best results.

Then collect and remove all the churned-up debris.

The tools

Dethatching machines

These machines have spinning metal plates that break the crust of the earth and lift the thatch from the lawn.

Power rakes

These pose a risk for weaker lawns, as they can pull up healthy grass. They have flailing blades and penetrate deeply into the lawn.

Slit seeders

These are sort of hybrid machines, and they’re mostly owned by professional lawn care concerns. They come with the best of both worlds – spinning blades for dethatching and circular blades for cutting grooves into the soil.

Sod cutters

Only to be used in extreme cases! You’ll need a complete renovation job once you’re done.

Vertical slicers

These champs slice through your lawn to pull up thatch. They’re what you’ll find on sports fields.

How much will dethatching set me back?

If you’re looking ay buying a machine, a simple, easy to use and mostly idiot-proof dethatching machine will set you back between $100 and $300. This all depends on the brand and the features. And, of course, the merchant!

If you’re okay with putting your back into it, you can get a proper but non-motorized thatching rake for around $40. Up it to a gas-powered model, and you’re looking at around $55 (if you rent).

Do I do it myself, or do I phone a pro?

Look, this is always the question, isn’t it? I hate tilling up the lawn I worked so hard putting down. So, I opt for a professional. Every time.

It’s quite simple though – if you can walk behind a lawnmower, you’re more than up to handling a dethatching machine. And if you’re going to do it yourself, the detaching machine is your answer.

Consider renting.

It’s done. What now?

Number one – remove the piles of debris. Seed the lawn properly and do proper topdressing.

The weather could slow it down, but ideally, you should start seeing the fruits of your labor in about a month.

Green and healthy lawn

How do I prevent the stuff from building up again?

Think about the grass you plant. High traffic areas or sports fields do well with Kentucky bluegrass. It grows like hell and establishes itself in no time.

If you plant perennial ryegrass or at least mix it in with your lawn if you have Kentucky bluegrass, it will drastically cut down on your thatch problem.

Test your soil regularly. Make sure the pH and the nutrient levels are up to par.

Check on your watering and your mowing technique. Your mower should never be too low. And don’t be too enthusiastic about the fertilizer.

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