Oct 21, 2024

I recently noticed while taking a morning walk that a neighbor had overseeded the bare spots in their lawn. In my opinion, this is very late for overseeding in zone 7A. Will they succeed or fail? I’ll update this post periodically so we can learn together.

Observations:

• The neighbor’s front yard has a lot of bare spots. Their tree is quite small, so the bare spots were probably caused by lack of watering during the summer heat rather than by too much shade.
• They spread peat moss in the bare spots, then sprinkled seed on top. The peat moss is dark, indicating that it is moist.
• They used a seed with a green coating. This is most likely intended to help keep the seed moist.

Initial thoughts:

• October 20 is at least a month too late for good germination, and too close to freezing temperatures at night (will happen soon).
• Spreading peat moss in bare spots will help keep their seeds moist. The green coating should also help.
• They should have sprinkled peat moss on top of the seeds, rather than putting the seeds on top of the peat moss. Seeds would make better “seed to soil” contact if they were under the peat moss, and would be less likely to dry out. The birds would be less likely to eat them.
• Because their tree is small, they shouldn’t have too much of a problem with leaves covering the seed and preventing germination.
• I’ll be surprised if they get good germination this late in the fall. And if they do, I expect the seedlings to be killed by frost.

October 28, 2024

• They are doing a good job keeping the peat moss moist, as indicated by its dark brown color- Birds don’t seem to be eating the seed – perhaps they don’t like the green coating?
• No germination so far. Assuming their seed is either rye or tall fescue, the seed should have germinated already or will very soon. If they planted Kentucky Blue Grass (unlikely), germination is still a few weeks away.
• Temperatures have been warm during the day (60s-70s), but cool at night (40s-50s). I do expect some germination, but slower than if they had seeded a month ago.
• They have managed to grow some weeds (including a yellow dandelion). This is expected when overseeding, because the peat moss and moisture create ideal growing conditions for both grass and weeds.

Oct 31, 2024

• Germination!! See the baby grass growing in the midst of the bare spots in the image below (look between the fallen leaves in the center of the photo). Click the photo to see a larger version.
• Unfortunately, only about 10% of the area they overseeded has actally germinated. Perhaps the remainder will germinate soon? In my experience, grass seed does not all germinate on the same day. Rather, it germinates over the span of a week.
• Daytime temperatures remain warm with no rain.

Nov 11, 2024

• No further germination has occurred. I’m honestly a bit surprised by this, as temperatures have been unseasonably warm this year. Grass requires ground temperates above 55 degrees F to germinate, and temps have been above that.
• Possible explanations for lack of germination:
  • Old seed. As seed ages, the germination rates decrease (for instance, in the first year 95% of the seed germinates; after two years, 80% germinates, etc). I don’t think this is the case because some patches germinated while many other areas did not. If the seed were old, I would have expected to see uniform but thin germination.
  • Seed eaten by birds (possible since they didn’t put dirt over the seed after spreading it)
  • Lack of moisture. They appear to be keeping their grass moist, but I normally walk by around 10 AM and it is possible their dirt dries out later in the day. They should be watering in the morning and again after lunch. Not sure if they are doing that.
  • Leaves smothering the seeds. They have done a decent job keeping falling leaves off the dirt (although the picture above does show some fallen leaves). I’ve actually had grass seed grow right through leaves! I don’t think this is their problem.

I will keep watching for any additional germination, but I don’t expect any this late in the fall (even with unseasonably warm weather).