Hi Chris!

Hard for me to tell from this picture, easier for you with the turf in your hand.

{{gwi:87173}}

If the thatch is more than 1/2" thick, consider dethatching / power raking. Less than 1/2" is fine.

Since you have applied your pre emergent, dethatching would void the barrier that the herbicide formed. Wait until Labor Day - apply preM again after dethatching to prevent poa annua.

(I have no confidence in that Craftsman, BTW)

Yes, too much nitrogen, especially applied too early in the season, will cause excessive thatch. Also excessive shallow watering will too.

Do get your sprinkler set properly. We suggest tuna cans because of the 1" walls. (easy and convenient - if you like tuna, LOL!) Set out several in 1 zone. Turn water on to that zone only and time how long it takes to get 1" of water.

Move to each zone repeating this. Sometimes water pressure is different in separate zones. Best to check now while doing the initial testing. Make notes if zones differ and adjust time accordingly.

Give it time to fully wake up. After you have mowed a couple of times, apply your fertilizer. If you haven't purchased it yet, ask for something with iron included.

>"we were told by the lawn service that the previous owners 'fertilized like crazy' "

You really should consider a soil test.
UMASS does a great test for only $13 and accepts non-residents. Get test *C* "Standard Soil Test w/ Organic Matter" which include the standard nutrients like N-P-K, micronutrients like iron and organic matter also. Your soil's pH is directly linked to how green the grass can be and you may be sitting on a phosphorous / calcium mine :-)
See link below.

Here is a link that might be useful: UMASS soil testing link

I think I would go ahead and take care of that thatch now to give the existing grass a better chance of thickening out assuming its kbg. The fertilizer and other amendments will have a better chance of working if they could get to the dirt. You can areate in the fall and overseed then.

Thanks guys (hi again Gary!) just defaulted to craftsman for ease of searching for my mower

Whats a good dethatcher to use?

Got some soil drying out in the garage and will get that in.

I'm going to be the dissenting vote here (Gary knows I do that "occasionally").

What I see isn't traditional "thatch". Thatch is most often the stalks of the grass, which don't break down easily. That looks like grass Blades more, which fits with the rest of what I think.

The grass is thin-bladed, which makes me think that we're dealing with a lot of a Fine Fescue. Here's where it comes together: fine-fescue doesn't like heavy fertilization, and will decline. The "fertilize like crazy" isn't a good match.

I'd dethatch anyway to get rid of the thatch AND the dead blades. I'd find out if you really have a lot of fine fescue and back off about 1/4 on the fertilizing if it is FF.

A little less might be a lot more (health) in your case!

>"Whats a good dethatcher to use?"

Walk behind rental units. Make sure it has spring tines installed - they do come with different attachments (knives and flail blades) but these other types are generally used in the south.

It's the raking and clean up that will break your back, especially on your sized property.

Andy brings up a great point. Like I said - I can't see it - but you can in person.
Use these two pictures for reference.

http://www.rcocomputers.com/websites/ryanslsc/images/thatch.jpg

http://www.lifeandlawns.com/wp-content/uploads/2008/03/thatch-plug.jpg

Be sure that it is needed.
A. The clean up is MUCHO hard work
B. Really beats your lawn up / initial stress.
C, What you have, an acre? You'll need a dumpster rental to dispose of all that much thatch, LOL!

I used to have Merion Bluegrass. It loved nitrogen. The more the merrier., but that caused a lot of thatch. Because of the Merion and my father owning a small lawn service company, we had a power rake. I'd be willing to bet, we would fill up 4, 55 gallon bags, weighing at least 50 Lbs each, just dethatching 1000 sq. ft.