As Bill the Cat would say, "Aack." First off, your watering may be part of the problem. You're loving it to death. The point of watering the grass, besides keeping it from going dormant is to encourage a deep root system. By your short and frequent waterings, you've encouraged your grass' roots to stay shallow and weak. Ideally, you should water once per week with a solid inch or so at each location. Typically, that will require an hour or so at each location. But you should check your own system using the tuna can method. Can you tell us what type of grass you are growing? It doesn't look good. But it might help if we could know that information.

Don't do anything else, including raking, until we figure some things out. Spraying the bermuda might have been a mistake. I realize you don't want bermuda, but it might be the most dominant grass for your area. It can be beautiful when properly cared for. Certainly it will overrun fescue every time. Where do you live? Dethatching is rarely necessary. Think of that "thatch" as organic fertilizer that you just took away from your lawn. I don't think that was thatch, but it's still not available to the lawn anymore. Some grasses can be killed out by dethatching, so we need to know what you have before you go any farther. Core aeration is unnecessary for seeding and very, VERY rarely necessary for any other reason. Whatever issue your lawn has that you think requires core aeration probably has a better solution. That grass with the dime looks far too dense to be fescue. And it looks coarse bladed to me. Can you dig down through the grass and tell whether you see runners across the surface? Really need to know where you live.

So you dismissed all core aeration studies that are for crop fields as irrelevant, then came along with your own crop field study that's relevant , because you say so. Show me a study on core aeration for crop fields. Tilling is not core aerating. I didn't present that OSU article for a discussion about aeration. In fact the one weakness is that it isn't specifically geared toward home lawns, so we have to make some assumptions. I'm the one saying it is hard to find any real scientific studies for a "home lawn." My interest in this article is more in the soil biology that explains why a biologically healthy soil probably doesn't require aeration. I guess this seems hypocritical to some people. Not sure why. As to your next point, yes, I say the soil biology presented in this article is completely applicable to a home lawn. Explain why it isn't. 1. In an average well maintained organic lawn, with no deficiencies, what is the average percentage of organic matter? When you say "organic" lawn I assume you mean any lawn, even yours, that has enough organic matter mulched in each year to maintain a healthy level of organics. I'm not an expert on what the exact organic level should be, but the number depends on the type of soil. Sandy soils will be hard pressed to get very high levels, while heavier soils can exhibit much higher numbers. I think morpheus' lawn is around 15%. Morpheus says 3 or 4% is borderline low, 5 or 6% is good and anything near 8% is excellent. 2. Is this level of organic matter sufficient to get in between all soil particles and prevent all soil particles from compacting and if so, what do you base that assertion on? I understand what you are getting at with these two questions, but again, you'vegotten something into your head that has no basis. You seem to think 100% of the particles must be linked to an organic particle in order for the soil not to need aeration. Nobody but you is asserting that. The article clearly shows the relationship between roots, bacteria, fungi, bugs and worms and all the other things that form macroaggregates. If you have lots of these macroaggregates around the root level, which is what naturally regulates oxygen, then you probably don't need mechanical aeration. Listen, the way science works is that you have to go on a hypothesis that may or may not be proven out over time. Eventually it becomes an accepted "law" or fact if it holds up. I've come to believe that this and other online forums are like laboratories where everybody contributes their experiences with their own lawn. Lawn companies and even universities have biases. Ask dchall about all this. He has been here the whole time and has seen a lot of what works and what doesn't. My position is that I am not going to do something to my lawn unless I have evidence that it does good. Otherwise you can do more harm than good. From the evidence I've seen in this forum, from doing other online research, and just observing problems different people come into this forum with, my conclusion is that there is no need to aerate if you are doing everything else properly. The nice lady, Lisa, started this discussion by saying she had summer fungus caused by over fertilizing ("live and learn"). She cut back on the fertilizer and started aerating. I think she is attributing the lack of fungus to the reduced fertilizer and the aerating. My reaction would be to get a Logan labs test and see if there are any soil problems, and then decide whether aerating is really doing anything. Again, if she has good soil biology and plenty of us never aerate, then why should she have to? I think too many people see lawn companies aerating and just assume it is a good thing to do. The article I presented from OSU suggests the increased oxygen can actually do harm. Scott's recommends you weed and feed in April. Do you think that is a good idea, too?

We need more information. Some grasses will spread to fill in the thin spots and some will not. Whether you seed again depends on what kind of grass you have. It also depends on where you live, so if you could answer those questions that would help us to help you. Fall is the best time to seed grass, so waiting is not a bad idea. Now is not a good time and every day that passes it gets worse...unless you have bermuda. Unless you have bermuda or centipede grass, then set your mower to the highest setting. That alone will help a lot. Fertilize in mid to late May but not again until September (Labor Day). Fertilizing in June, July, or August is a no-no because it adds chemical/salt stress to an already heat stressed plant. Wait. Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall. Lawn services are no better than their employees. Most follow the book - one size fits all. Once you get the hang of watering, mowing, and fertilizing, it's pretty easy. Then if something goes wrong, come back here and ask questions. When you take lawn pictures, take them on a cloudy day.