One Inch ( 1" ) or more of Thatch, is Too Much

Is the thatch in my yard too thick?  One inch or more of thatch is not good for your lawn and steps should be taken to reduce the thatch layer.

If you are wondering if thatch is an issue in your yard, measuring will give you the answer.  Pull a plug or use a shovel to get a sample of the soil/thatch/turf layer from your lawn.  You will see there is a grass layer, crown layer, a thatch layer and a soil layer. 

If your thatch layer is over 1” thick then you have a thatch problem and you should start working to reduce the thatch layer.

Other cools season grasses that spread via rhizomes include:  creeping red fescue and creeping bentgrass (bentgrass varieties aren't great for our MN lawns, they are used primarily for golf course fairways, greens and tee boxes, which are mowed extremely low/short).  The other cool season grasses we use for our lawns, including:  perennial ryegrass, tall fescue and most of the fine fescues (other than creeping red) are bunch type grasses, that typically don't produce very much thatch.   

Solution:  Regularly aerate your lawn to reduce soil compaction and break up thatch layer.  Core aeration is the process of punching holes into the soil and pulling out little plugs (cores) to reduce compaction.  This is one of the best things you can do to prevent thatch from becoming a problem in your yard. 

There's a reason golf courses in MN aerate every single year, because it matters and it works!  FYI - you do not need to rake up or remove the plugs, they will break up and disappear on their own, within about 2 weeks. 

How often should I aerate my lawn?  Ideally, you should aerate your lawn every year.

When should I aerate my lawn?   Late Summer or early fall is the best time to Aerate in MN.

2)  Soil PH:   Acidic soils with pH 5.5 or less do not support large populations of the microorganisms needed to breakdown larger amounts of thatch.  Ideally, you want your soil pH to be between 6.0 - 7.0 for growing turf in MN. 

Solution:  Lime application treatments will help increase the soil pH / reduce acidity.   

3)  Heavy Sand and Clay:  Soils that consist of heavy clay and soils that are extremely sandy, also do not support large populations of thatch eating microorganisms. 

Solution:  Lawns with heavy clay or very sandy soils can be greatly improved by topdressing with topsoil containing lots of organic matter or compost.  

4)  Over Fertilization:  Over fertilizing with nitrogen, particularly applying too much fast release nitrogen at one time, can lead to excessive growth that builds up the thatch layer too quickly.

Solution:  At KG Landscape, we spread out our nitrogen fertilizer applicators over several treatments throughout the season.  We call this spoon feeding, which means that we apply the total amount of desired nitrogen over several treatments throughout the growing season, during optimal times, rather than all at once. 

We also use fertilizer with slow release forms of nitrogen, such as coated urea products, corn gluten and other organic based fertilizers in order to prevent problematic excessive growth.  These are all practices we incorporate into our fertilizer and weed control packages      

5) Soil Compaction:  Heavily compacted soils have less oxygen available to the grass roots, than uncompacted soils of the same type.  This means that compacted soils have less oxygen to support healthy populations of the microorganisms that decompose lawn thatch.

Solution:  Regularly aerate your lawn to reduce soil compaction and break up thatch layer (every year if you can).

6)  Mowing Practices:  Small clippings left weekly are not the issue here.  In contrast, leaving thick layers of grass clippings (think of cutting a hay field) is problematic for a number of reasons, one of which is that it will cause thatch problems.

Solution: When mowing, only remove 1/3 of the length of the grass each time you mow.  If the grass does get too long and clippings become thick or clumpy, then you can bag them and remove the clippings. 

Tip: wait for the grass to dry before you mow.  Mowing when the lawn is dry helps produce finer and more thoroughly mulched grass clippings, in comparison to cutting when the grass is wet.

Core aerating your lawn is something you can do every year to reduce compaction and prevent thatch issues.  Walking on and mowing your lawn creates soil compaction that should be managed annually to help maintain a healthy lawn.  If you are not able to aerate once each year, then we recommend aerating at least every other year.   

1)   Aerating your lawn helps provide the oxygen that is needed for microbes to breakdown and decompose lawn thatch.

2)  Aerating a lawn breaks through the soil and thatch layer, allowing water, nutrients and air to reach into the rootzone          of the grasses, helping to establish deeper root systems and promoting new growth. 

3)  The best time of the year to aerate your lawn in MN is late summer / early fall

Learn more about our aeration services



How to know if compaction is a problem in your yard?  An easy way to check for yourself, is to try to stick a screw driver 5" deep into the soil in your yard.  The screw driver should slide in fairly easily.  If so, then your soil is likely not too compacted. 

If it takes a lot of force to slide the screw driver all 5" down into the ground or if it's not possible at all, then your soil is too compacted.  If this is the case than its time to aerate your lawn.  Aerating will greatly benefit your lawn by loosening / reducing soil compaction. 

If you aerate regularly, you should never need to power rake your grass in MN.  However, if you already have 1" or more of thatch and want to remove it quickly, then power raking can help do that and push the reset button.  Power raking is definitely the most aggressive way to remove build up thatch and in our opinion, its only useful in certain situations.   

Generally, we don't believe power raking in all that helpful for lawns in MN.  Here's why:

• Power raking doesn't address the cause of the thatch build-up, which is typically compaction that prevents soil microbes from effectively decomposing thatch. 

• Power raking and the clean-up it requires is a lot of added work and expense just to remove thatch that will eventually breakdown naturally in the soil.

• Power raking also removes the good thatch layer too.  Remember that some thatch is really good and a healthy lawn should have around a 1/2" layer of thatch here in MN.

• We've yet to see a thatch problem in the twin cities that couldn't be remedied by aerating.

If you have small areas in your lawn where thatch has built up too thick, using a thatch rakes actually works great. 

Should I remove all of the dead grass in my lawn during a spring clean-up?  Save your time and energy and skip the hard raking, because there's typically no need to rake your yard just to remove dead grass the spring.

Using a rake on dormant grass can damage the lawn by pulling out grass roots and crowns, before they've had a chance to green up and start growing again. 

Your grass may look brown or tan in the early spring, but it's not actually dead.  This is because our grass goes dormant in the winter, by storing energy in their crown and roots, before letting their shoots/grass blades die back.  The tan dead grass you see is just last season's dead grass blades that haven't had the chance to breakdown yet, because the ground has been frozen. 

Once soil temps warm up in the spring, the dead grass material from last fall will quickly be broken down by microorganisms in the soil and you wont see it anymore.  This is why, spring dethatching is typically unnecessary in MN. 

We don't recommend dethatching in the spring unless the thatch is 1" thick or greater.

Use a leaf blower instead of hand or power raking in the spring to remove excess debris, it's easier too.  Like raking, leaf blowers do a great job of fluffing up your grass in spring, which will make lawn look a lot nicer after being matted down all winter. 

Another benefit of using a blower to fluff up matted down grass, is that this process may help get the grass growing a little faster in the spring.  This is because the matted down grass and debris can sometimes act like a blanket, insulating the cold soil from the warm spring air.  Fluffing up matted down grass areas lets the warm air and sun heat the soil a little more quickly, speeding up the process of getting your grass growing again in spring.