Hello Steve,

First, without a picture of your weedy grass invader, it is not possible to positively identify it and therefore we cannot offer any conclusive advice. If you would like to send pictures of the grass in your lawn (from a distance, close up of an isolated plant on a white background, and a close up of the blade/stem junction), we may be able to confirm the type of grass you have. See the image in the following page to see the detail that is necessary for identification: https://www.canr.msu.edu/ipm/diseases/quackgrass?language_id=#gallery

This is important because treatment of tall fescue and quack grass are considerably different.

But. let me assume you do have quack grass. Quack grass is a perennial weedy grass that spreads (extremely well) by underground rhizome growth. The underground rhizomes can travel several feet to result in another clump of quack grass. It is extremely difficult to control because of the underground rhizomes that spread a great distance and the smallest piece can re-stablish growth of a plant. Quack grass has large leaves and grows quickly to reach above the desirable grasses, absorb sun and gain strength. By fertilizing lightly and frequently you can stimulate the desirable grasses, boost their growth and help them compete better with the quack grass. The other aspect of this approach is very frequent mowing. You need to ensure that the quack grass does not reach above the desirable grasses and regain strength. If your grass is thick but the quack is not declining, you may not be mowing frequently enough. The specifics of this approach are detailed in the following article: https://www.canr.msu.edu/news/quackgrass_control_in_turf#:~:text=By%20increasing%20the%20vigor%20of,most%20part%2C%20make%20it%20disappear.

This article also details the control methods for physical removal and non-selective herbicide treatment. Unfortunately, in your case, non-selective herbicide treatment may mean a complete kill and re-hydroseed.

How did the quack grass get in your lawn? I would likely look to the soil preparation. If the area was a field that was tilled or scraped and leveled, the rhizomes might have been left in the soil after scraping or tilling. If topsoil was brought in, the rhizomes could have been in the topsoil if it was not properly screened. Right after hydroseeding you probably had a small percentage of quack grass that has been multiplying ever since.

You mention your watering. How long you water is related to how much (in inches) of water you apply to the lawn. Grass plants react to the amount of water, so it is important to know how many inches of water you are applying. This article explains how to perform the “tuna tin” test to determine how effective your watering regimen is: https://www.canr.msu.edu/news/how_much_water_does_your_lawn_irrigation_system_apply

Hello Steve,

I would try the least obtrusive method of remediation first – the nitrogen and frequent cut method. Provided, of course, that you can cut frequently and regularly. You need to commit to cutting the quack grass every time it starts to grow taller than the lawn grass. From the second reference in our first response:

Option 1: Management

Many folks have effectively "eliminated" quackgrass by masking its presence in the lawn. This is usually accomplished by increased nitrogen fertilization and increased mowing frequency. (Just what everyone wants, mowing more often!) This approach has been implemented with relative success by more than a handful of turf managers. The idea is that the quackgrass only has a competitive advantage when the desirable grass sits idly by. By increasing the vigor of your lawn you will choke the quackgrass, make it darker green and, for the most part, make it disappear.

The photos you shared are consistent with quack grass. Quack grass seed is viable. https://www.canr.msu.edu/weeds/extension/quackgrass

I would not mulch if the quack grass is showing any seed heads, but if you mow frequently and there are no seed heads showing, you should be safe to mulch. You are correct – mulching is a good cultural habit that increases the health of a lawn.

Ant nests and hills in the lawn are more unsightly than they are detrimental. It is difficult to say whether the ants are taking advantage of bare spots in a thin lawn or if the ants are creating thin spots in the lawn. It is more likely the former rather than the latter. Treatment to address the ant presence is not recommended.

Hello again, Steve,

Every season varies for lawn growth, but a general rule of thumb is if you need to cut your lawn, it is the growing season. This is typically mid April to late September.

3 to 4 inch mowing height is optimal for most turf grasses.

If you are going to apply light nitrogen every two weeks, you should not apply the “four times” fertilizer in addition. You should, however, perform a soil test to find out how much Potassium you should apply to your lawn. In Michigan it is illegal to apply Phosphorus to an established lawn. The numbers on the bag are Nitrogen – Phosphorus – Potassium. You should never apply a product to your lawn unless it has a 0 in the middle position. The soil test will tell you total nitrogen and potassium to add on a yearly basis. It will also measure your pH and organic matter and advise on how to modify those as well. Details on MSU soil testing can be found at: https://www.canr.msu.edu/news/soil-testing-returns-through-msu-extension

Granular nitrogen products tend to be slow release and are less likely to burn your lawn. I would recommend against a water soluble liquid fertilizer application.

One final comment. We can usually find several articles from reputable sources about a specific care regimen. This frequent low dose nitrogen and frequent cutting plan is only mentioned in a few articles, I hope you have success with it.