I overseeded with TTTF in September, and the lawn looked amazing. Went on a 2-week vacation in mid-October, came back, cleared the leaves, and noticed some yellowing. I treated it with a hose-end fungicide just to be safe, but I’m not sure what’s going on. Could it just be the grass starting to go dormant? I sharpened my mower blade and cut the grass right before taking this picture. Located in Chicago.
Mulching leaves into the lawn is greatly beneficial for several reasons:
- It adds organic matter to the soil, which improves nutrient and moisture retention, alleviates compaction, and helps with drainage.
- It provides many nutrients that are costly and difficult to supply, especially micronutrients, since trees are generally better at nutrient uptake than grasses.
- It serves as an effective form of pre-emergent weed control, particularly against broadleaf weeds, and can hinder future poa annua and crabgrass growth.
According to MSU, you can mulch up to 6 inches of leaves into your lawn at once, depending on your mower’s performance. In most cases, it’ll be faster than raking or bagging.
Here are some tips for effective mulching:
- Start the fall season with a high mowing height (it’s too late for this season, but helpful for next).
- Use a mulching blade, which is typically included with new push mowers.
- Plug the side discharge chute to prevent leaves from blowing out the side.
- Don’t let leaves pile up; weekly maintenance usually suffices.
- Ideally, mulch leaves when they’re dry. A little dampness is okay, but excessively wet leaves are not ideal.
- Pine needles and walnut leaves can also be safely mulched, contrary to popular belief that pine needles acidify soil.
- If you encounter clumps of matted leaves, break them apart. Kicking them works, or you can use a rake/blower.
The common argument against mulching is that it smothers the grass. However, if you’re doing it correctly, this shouldn’t be a concern. Just make sure not to mulch if you plan on dormant seeding in the future.
Looks good, to be honest. How does the curb and cement area look?
Mika said:
Looks good, to be honest. How does the curb and cement area look?
You mean the parkway? It looks fine!
WARNING to those in the northern hemisphere: The window for SAFE seeding has closed in most cool season zones (except for the southern SW U.S.). The next recommended window is dormant seeding when soil temperatures fall below 50F/10C but before the ground freezes.
@Bao
A lesser version of this 
@Bao
I haven’t seen any worms yet!
Soren said:
@Bao
You might want to check for them by moving your hands through the grass; I suspect it’s moth larvae that could harm the grass. You may want to scarify and collect the clippings, but it should hold up. It might be beneficial for birds and wildlife too; consider putting out a bird feeder—they’ll feast on them!
I overseeded my entire backyard in September, and it’s been turning yellow like this for a few weeks. Initially, I thought it was overwatering or a fungus, but I’m also wondering if the new grass is just going dormant. Hoping for the best this spring!