Kay Lancaster writes:
First, cut some sod samples to see what's going on with the soil, in both a
green and a brown patch. Water first with a sprinkler for 15 minutes before
trying to cut the sample, and then wait 15 minutes before cutting. Can you get
a spade in easily? If so, it probably doesn't need aeration, unless you've
got traffic lanes (a dog patrolling your fencelines, a mailcarrier wearing a
path, etc.). Is there a difference between the two samples in how far the water
penetrated into the soil? Is there a lot of dead stuff (like more than 1/2 inch)
just above the soil in brown areas making a layer that water doesn't penetrate?
If not, you don't have thatch (and chances are, you don't have thatch anyhow --
unless you've been feeding the lawn quite heavily.

Hmmmm, well the patches are irregularly shaped and randomly scattered
with each alive and dead area maybe only about a couple square
feet. Even the live areas aren't exactly lush (they still are thinned
out and have brown within them, just not all dead). And btw, we don't
have a dog or anything like that...

I did fertilize 3 times this spring (once with Scott's Stage 1 and
twice with Scott's stage 2). I used the second application of Stage 2
because I feared that after the huge rainstorms in May/June (we live
in the Boston area) that the anti-weed protection had dissolved and
that the fertilizer had been used up by the rapid initial growth
caused by the rain. The lawn did grow quite lusciously at first
probably due to a combination of rain and fertilizer.

There are 2 additional possible causes to our problem.

First, our lawn lies on a sloping hill surrounded by maple trees so
the soil tends to dry out; however, as above we had a VERY wet
May/June and I have been watering the lawn since 3 times a week for 50
minutes. I am hesitant to water more due to the cost of water and I
was told that better to water fewer times for longer to encourage root
growth and discourage crab grass. Also, even on the other side of the
house where the lawn is flat, the grass is pretty anemic with a lot of
mixed in dead strands (just not as severe or patched as in the sloped
areas).

Second, because of the near constant May/June rains, the initial grass
grew pretty lushly to about 6-8 inches high before I had a chance to
cut it. I then cut it back to the medium setting on my mower/mulcher
so I don't know if I "shocked" the lawn too much. This tends to leave
about 2-3 inches of lawn.

Interestingly (and perhaps this is the KEY), is that while the lawn
was growing extremely fast and green during the April/May rains, it
has hardly grown anywhere (even in the relatively green areas) over
the past 8 weeks - so much so that when I mow there is very little to
cut. Even in the non-dead areas, the grass is thin with mixed in brown
strands and very anemic growth.

So it seems like something "shocked" almost the entire lawn causing
some areas to die and other areas to fade and stop growing.

Regarding thatch, what I mean is that there is dead grass that is
lying in a light mat on the ground, particularly in the dead areas --
most likely representing a combination of grass that died and the
longer grass that I cut earlier in the season during the rains.

Hopefully, this is helpful in adding more detail...

http://www.extension.umn.edu/distrib...re/DG1123.html

Were the brown areas quite green in cooler temps, and the areas that weren't so
green are now green? If so, that suggests you've got a mixture of warm season
(Zoysia, buffalo grass, crabgrass, etc.) and cool season (bluegrass, fescues)
in your lawn, and they're reacting quite predictably to summer temps.

Again areas are random with no apparant difference.


If you get back to us with the results of that spade test, we can suggest
some better ways of going on.

Personally, I'd start with a soil test, especially if you've not been liming and
fertilizing regularly. That's no matter what the spade test shows. I'd also
pull a sample for a shake test, to determine particle size composition of the
soil.

My gut feeling is you've probably got a mixture of warm and cool season grasses;
if the warm season grass is crabgrass (it'd be green now in hot weather), it's
an annual and can be "cured" with proper fertilization, mowing and overseeding.
Might want to poke around on the web and match pictures of blooming/seeding
grasses in your lawn to some of the common lawn weeds.

Assuming you've got crabgrass, I'd suggest running through the areas with a
tiller, scattering (by hand)
in good fresh lawn seed of desirable species, firming up the soil, and
then watering this fall. Apply lime and a good "starter fertilizer" without
pesticide this fall; lime and a spring fertilizer next year. And get the mower
blade sharpened... one of the biggest causes of ratty looking lawns.

Kay