You write in just seldom enough that we forget where you live and what kind of grass you have. For some reason I'm thinking fescue in Philly, but I could be off by a lot.

Did you moisten the grass before applying the weed n feed? If you did then you might get some weed control out of it. The way you describe your front lawn in previous posts and this one, the weed n feed was a blatant waste of herbicide. All you need to do for a nice lawn is wait until mid April and spot spray the few weeds you have. The reason for waiting is that you might get more weeds in the next month and have to do something else. It just uses less herbicide. If your lawn was dry when you applied then you don't have any herbicide effect at all. This mistake is very normal for weed n feed. It is hard to keep the weed leaves moist while at the same time pushing a spreader around. For this and other reasons none of the lawn forums (except those selling products) recommend using weed n feed.

I don't think you did any damage with the timing. Crabgrass control goes down very early. Spot spraying with Weed-b-Gon or something similar is usually done 45 days or so later. Then the FIRST fertilizer app of spring should go down 45 days after that (Memorial Day).

What was your reasoning for core aeration? Do you have hard soil or did you do it because everyone else was doing it?

I have KBG Fescue and Rye cooler season Grasses its a sodded lawn back in October of 2008 and its super thick that is why I Aerate its been 2 yrs since I did it though so it needed it, I was wondering if I put down them to close together..and what is worse case scenario, it will just grow out if I burnt the tips right? It's a super healthy lawn, I will attach a pic I just took

Am I understanding correctly that you applied pre-emergent at the end of March and then core aerated a week ago?

Yes! my ? was did I put weed and feed down to close to the crabgrass control not about Aerating, this is my lawn now for beginning of April

my ? was did I put weed and feed down to close to the crabgrass control not about Aerating

You're right, my bad.

I feel a little stupid. Maybe my internal calendar broke, but it is mid April right now. So your timing for the herbicide was fine. I just think weed n feed isn't a good experience for too many people. Watch the lawn at the end of May to see if it is looking yellowish. Applying fertilizer in the early spring can lead to late spring yellowing...which requires still another dose of fertilizer. The best practice is to wait until late spring to apply the first dose. Then in the fall it gets two doses of fertilizer (Labor Day and Thanksgivingish). The majority of the N should go down in fall.

But enough about your beautiful, healthy front yard. Tell us about your back yard. How does it look and what are your plans for that this season?

I only weed and feed to keep the neighbors dandelions from coming over to my lawn :x I am going to put one more dose down late may after I put Grub Ex down, you think that would be okay? why does it lead to late spring yellowing?? I never had that happen in my Life maybe the end of summer as I do Not put anything down all summer, maybe ,,Milorganite but that is it. Thanks ;)

Lol I DO so Listen "sometimes" I am Italian ha ha It's in my blood not to listen at times.. ( have to blame something ) ;) anyways, everything you said makes perfect sense! However, my lawn is Sodded from 2009 and our soil here in Pittsburgh is like clay and w the Sod and the Clay like soil its not good to Not Aerate in my humble opinion :) I feel good when I Aerate, and I know what you mean about the Grub Ex, BUT I had damage from Grubs 2 Falls ago so I use it as a Precaution.. I wish I waited to weed and feed but I got nervous so I did it, Do you think I will have fertilize again in may?? Thank you for taking the time to write me, I really do Appreciate it!