Bad Case of the Thatch

Visited a lawn today.
On the front was a patch of exposed lawn.

This lawn was sodded in the past couple of years. But the thatch layer is very dense and thicker than it should be. Thatch is good and bad.

A little thatch does help to reduce moisture loss due to evaporation. A small amount can help to cushion the soil from excessive traffic and reduce the risk of compaction.

Too much thatch, however, can act more like a thatch roof. In this case, it prevents rain and water from reaching the root zone. Rain will wash off the lawn rather than seeping into the soil. Excessive thatch also reduces the amount of beneficial oxygen that can reach the roots. It can also impede the movement of fertilizers to the roots. A thick layer of thatch also is where insects like chinch bugs can reside and then cause extensive damage to the turf. And lastly, grubs, while we think of them as eating grass roots, do seem to enjoy feeding on thatch as well. This make "thatchy" lawns more likely to experience a grub attack.

Thatch as seen in the picture above is best removed by core aeration. A dethatching will only treat the symptoms. The real problem is a lack of oxygen to the microbial population that normally decomposes the thatch layer. By improving the soil structure with an aeration, the excess thatch will disappear.

Thatch Problems

Thatch can be a problem in your lawn.

We inspected a lawn this week that was just not responding the way is should. On inspection we found that the lawn had a very heavy layer of thatch.

Now by thatch we mean that layer between the soil and the green part of a lawn. Some people refer to dead or yellow grass blades as thatch. As in, "My lawn has a lot of brown in it. It has a lot of thatch." Well, that is just dead grass blades. Thatch is normally not visible until you start scratching the surface.

Thatch can consist of roots, stems and other organic matter. Some thatch is a good thing. A little bit will help prevent moisture from escaping too readily on a warm day. Somte thatch acts a cushion to prevent the soil from getting too compacted from foot traffic and mower wheels- anything that will push the soil down and drive the air (really we mean oxygen) out of the soil pores.

However, too much thatch can be detrimental to the health of the lawn. Too much thatch acts like a thatch roof and prevents water from penetrating into the soil. The rain and irrigation instead are carried off the lawn and into the storm sewers. Too much thatch prevents fertilizers from reaching the root zone. Too much thatch also increases the likelihood of disease problems. Chinch bug like to hide in the thatch. White grubs feed on grass roots as well as thatch. Anecdotal evidence would suggest that European chafer adults seem to know if a lawn has a lot of thatch and may be more likely to lay their eggs in lawns with excessive thatch.

So, how do you get rid of thatch and keep it away? First off, thatch is not caused by leaving the clippings on the lawn. Secondly, we don't normally recommend usin a dethatcher to remove thatch. While a dethatcher will indeed remove the thatch, this is really only a temporary solution. The thatch may be gone, for now, but without tackling the root causes of thatch, it will be back.

Our recommendation is to core aerate the lawn. Aerate it heavily, i.e. aerate it twice all at once. This will put that many more holes in the lawn. It will remove that many more cores. Each hole will allow oxygen back into the soil. This will encourage the bacteria and other soil fauna to grow and multiply so that they can decompose the excess thatch. Each core that lands on the surface will now "topdress" a small section of the lawn. The soil there will also encourage soil organisms to do their work. Grass roots will quickly grow into the core holes where there will be a better mix of moisture and air. As the grass roots flourish, so the lawn will become healthier.

If you want to speed up the process, the addition of more soil to the lawn surface will mean that the whole lawn will be topdressed instead of just the areas that have the cores. At the same time, sprinkle some grass seed over the lawn. Grass seed that fall into those aeration holes always has a better chance of growing. They are less likely to dry out, less likely to be snatched away by a hungry bird, and more likely to continue growing once they sprout.

In a few weeks, the lawn will start to turn around. This is not an instant cure, but it is the first step to a green, healthy lawn.

If you have a lawn/tree/shrub that needs some Tender Loving Care- get The KING OF GREEN:

Turf King Home

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Do I need to rake my lawn?

Raking is good for the lawn. Raking is mainly a grooming exercise. And it can be exercise. Plus it gives you sunshine and fresh air (unless you like raking in the rain). Raking removes the dead grass blades. Once the dead blades have been removed, the lawn will look greener, even though you have also removed some green grass blades.

Raking is also a “pruning”. Just as trimming a forsythia bush will stimulate growth, raking a lawn will prune stems of grass and will also stimulate growth.

Is it absolutely necessary? No. The lawn will not look as green until more new growth starts, but the lawn will still survive. My lawn is huge and I never have time to rake, I don’t like raking, and so I don’t.

Dethatching is a form of mechanical raking. Generally, I find mechanical dethatching to be a little unnecessary. Many people see the dead grass blades from the winter and will say “My lawn has a lot of thatch.” As lawn experts, we call that dead grass blades. Thatch to us is that layer of stems, roots and other stuff between the green part of the lawn (the grass blades) and the soil. Some thatch is good as it insulates the soil from extremes of temperature and reduces moisture loss. Too much thatch (TMT) acts like a thatch roof and can prevent water from penetrating the root zone. TMT also provides protection for insect pests and can increase disease incidence. TMT accumulates because of the lack of oxygen and the proper micro organisms to break it down. Rarely is TMT caused by not removing the clippings. Return clippings to the lawn as this will better utilize the nutrients in the clippings and increase microbial activity.

If you have a lawn/tree/shrub that needs some Tender Loving Care- get The KING OF GREEN:

Turf King Home
Click here to Request a Quote Online -

or call us at 905.318.6677 or 1.888.TURFKING (887.3546)

If you would like more information, please Contact us

Follow us on Twitter  http://twitter.com/turfkingofgreen

Join our Facebook page  

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