The best time to dethatch your lawn in Minnesota is mid-September. Depending on where you live, you may also be able to dethatch in mid-to-late August, or whenever thatch is more than a half inch deep.
Thatch chokes grass, depriving it of the oxygen, water, and nutrients it needs to survive and thrive. And timing is important.
The best times to dethatch, by region in Minnesota
The University of Minnesota recommends dethatching from mid-August to September when grass is growing most vigorously. That is a general guideline.
You can also dethatch in the spring, but doing it in the fall is better, especially if you’re also going to overseed. Dethatching before the winter keeps your grass strong by encouraging all-important root growth.
Although it’s not the only important factor, soil temperature can be used as a decent guide of knowing when to dethatch. The best soil temperature for dethatching is between 50 and 65 degrees Fahrenheit for Minnesota’s grasses.
Here’s when each part of Minnesota has a soil temperature of 50 to 65 degrees Fahrenheit:
| Northern Minnesota | Mid-August to early October |
| Central Minnesota | Late August to mid-October |
| Southern Minnesota | Mid-September to mid-October |
The further south you go, the longer the summer. Therefore, while you can dethatch as early as in mid-August in northern Minnesota, you have to adjust your timing accordingly in central and southern Minnesota. So even though the University gives you the green light in mid-August, it might be a wise idea to wait until mid-September (or late August) if you live in central or southern Minnesota.
The right conditions for dethatching
Still not sure if you should go ahead and dethatch? You don’t want to do it at the wrong time of the year and spend even more money. Use this checklist to decide:
| Soil temperature | 50 to 65 degrees Fahrenheit |
| Season | Early fall (mid-August to September depending on area and your soil temperature) |
| After | Mowing your lawn a little shorter and light irrigation |
| Before | Aeration and overseeding |
Why dethatch?
Just because thatch builds up over time doesn’t mean you need to get rid of it. A small level of thatch is healthy; it acts as mulch.
However, if you have thatch thicker than ½ of an inch, it can cause problems. Your grass may become unhealthy from not receiving enough nutrients, air, and water. If your thatch is too thick, you need to dethatch.
Find out your thatch thickness by removing a pie-shaped wedge from your turf. Then, measure the thickness of the thatch.
Check out our month-to-month care guide for more information.
Get the job done with a pro
If you want to dethatch on your own, take some time to reconsider. Our cost guide estimates that it might not be financially worthwhile to do it yourself. Plus, there’s the intensive labor and research you have to do in order to not make a mistake and end up spending even more money.
Minnesota’s lawn care pros are ready to give you an instant quote. Find a pro near you.
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