Every lawn service seemed to be going full steam dethatching all their customer’s lawns this week, but why, and why are people paying for the service?

Studies from turf divisions of top-rated ag schools (as well as turf companies) agree on a few key points:

1. Some amount of thatch – usually 1/2″ or less – is, as Scott’s puts it, “actually beneficial; it acts like mulch to provide insulation from temperature extremes, helps keep moisture in the soil, and provides a protective layer of cushioning.” It also helps prevent weed growth and will help maintain a healthy system of microbes in your lawn.
2. Allowing grass to fall on the lawn, rather than bagging and removing the grass clippings, is the right thing to do because those clippings provide valuable nutrients to your soil as well as organic material. So says Scott’s, Bayer, Jonathan Green, UMass and plenty of others.

So why pay for detatching?

“Dethatching is good for the soil!” – As noted above, studies show that dethatching or “power raking” is actually removing beneficial material from your lawn, unless you’ve got thatch 3/4″ or deeper, which is often due to over-fertilization, typical of “mow and blow” lawn service treatments which kill the microbes your soil needs.

“We overseed at the same time, and dethatching creates better contact with soil.” – That’s partially accurate but studies (as the condensed table below by UMass) show, it doesn’t do a good job of it. Core aeration, which most companies aren’t doing this time of year, does a MUCH better job.

“Dethatching helps reduce compaction of soils.” – Again, the table above shows that is entirely inaccurate.

“People don’t want to see any dead grass in their yard.” – Well, it is hard to argue that one. If you’re unwilling to see any tan in your yard for a few days before the grass greens up, then paying someone to run a detatcher, I suppose, is an option.

I prefer to let nature do it’s thing, sometimes by doing nothing and sometimes with a little help from core aeration and compost (and/or some fertilizer) and, of course, leaving most of the brown grass that will help protect and enhance my yard for years to come.

Usually, paying for dethatching is the wrong thing to do for the health of your lawn and wallet.

If your lawn is more of a typical suburban plot, hopefully made smaller thanks to lots of flower and vegetable gardens, then a manual core aerator makes a lot of sense, both logically and financially. These units cost around $25, probably less than it costs for the ‘mow and blow’ crew and definitely less than the cost of renting a power core aerator for a few hours. They take up little space in the shed or garage and since it is always on hand, I can wake up any random morning and decide that today is the day I’ll spend 30 minutes to aerate my lawn. (Yes, it takes me about 30 minutes to do my entire lawn.)

Core aerators actually take a plug of soil from the lawn- allowing air, water and nutrients to penetrate the soil. Early spring and early fall this is a great way to help your lawn. Unlike the dethatcher, these are really helpful in most yards, especially if you’ve got lots of traffic on them.

I will say that:

1. The link above is to the unit I own. I do not get any payments for promoting it and I don’t get any money from Amazon for linking to it.
2. As shipped, that unit didn’t work well. The tines kept clogging with material. Using a hack saw I cut about 1 – 1.5″ off the tines and it has worked great since then, for about three years now.
3. After you use a core aerator, it looks like a flock of geese had a party in your yard. The cores fall apart within a few days though, so it doesn’t bother me, especially because in early spring we don’t usually have many visitors wanting to spend time in our yard.

Whether you choose to core aerate or not, dethatching is probably not anything you need to worry about.