I stripped and regraded my front lawn this fall while installing sprinklers and reseeded in October. At first, the grass was a deep green, but now I’ve noticed patches of yellow. The lawn had about 60 days of growth before it got cold, and there’s been plenty of rain. I’m unsure if this color change is something to worry about or where to start.
Based on what you’ve described, there are two main possibilities:
- Different grass types can react differently to cooler temperatures, lower sunlight, or dormancy.
- Variations in soil texture, especially more than 2 inches deep, can lead to roots growing at different depths. Darker green areas likely mean deeper roots.
From the patterns you’ve shown, I’m leaning toward the first possibility. Even if it seems unlikely given the seeding, this might have happened because:
- For some reason, perhaps due to moisture and temperature, one type of grass became established more quickly than the other. You’d think the lighter green spots would be noticeably thinner, though, unless you seeded excessively (which you should avoid).
- You might have had some poa trivialis that revived from stolons quicker than your seeds germinated, which means it could choke them out.
If it’s about root depth, then it’s primarily a matter of time, watering deeply but infrequently, cutting grass high, and providing good nutrients. If it’s poa trivialis, I have a guide here: https://www.lawncarecom/r/lawncare/s/Fd7uQqU64S
That looks a lot like what I’ve experienced. I’m not sure if it’s poa, shallow roots, or just older grass types that aren’t dark green and don’t mix well. It can be frustrating.
Have you fertilized since seeding?
Cruz said:
Have you fertilized since seeding?
No, because it was late when I seeded, so I decided to skip another round of fertilizer. I wanted the grass to focus more on developing roots instead of growing leaves.
That said, the Pennington Smart Seed I used is coated with starter fertilizer, so there was some included.
@Dayton
Got it. I’ll go with what Niles mentioned but expand on it. You might have a mix of poa annua or trivialis, or it might be a soil issue. I did a full renovation in your area two years ago using perennial rye and had similar results. I found that after regrading, I noticed discoloration after the first month. When you regrade, you’re altering the soil’s top layer where established roots are. This can affect how new plants grow. In your area, with the higher rainfall, nitrogen deficiency can show quickly, especially during a good fall growing season. After I noticed lighter green areas in some spots, I fertilized and within a few days, everything returned to dark green. After two weeks, it happened again, so I fertilized once more. My thought was that the newly filled low spots were getting better soil, leading to quicker nutrient consumption than the areas that were scalped. The next spring, everything evened out well. It may be different for you, but I don’t think you did anything wrong, and your lawn should be fine. If you want to test something out, try a little nitrogen fertilizer in a small 3-foot square in one of the yellow patches. Since your grass doesn’t truly go dormant in winter, it could use the extra nutrients.
It’s winter now. Dormancy isn’t always uniform, especially when you have a mix of grass.
Val said:
It’s winter now. Dormancy isn’t always uniform, especially when you have a mix of grass.
That does make sense, but I see other neighbors with green lawns all year. While dormancy is normal, are there ways I could try to keep my lawn greener for longer?