Does sod "wear out"?

 Hello:
     When I moved into my house about 20 years, I had it sodded. Over
the last 4 or 5 years, I have noticed that it was getting thinner and
thinner, now there are some fairly large areas that are bald spots. At
first it was sorta like guy going bald, where you could tell it was
thinner, but no obvious bald spots. Now it has continued on.
    I have it fertilized, I sprinkle when needed, I don't see any
correlation between the thinning spots and shade (we back up to a farm
field and share the tree line), I have had it aereated and over seeded
twice during the time it has been getting worse.
    Any suggestions? Questions?

 
Insect damage would be a possible suspect.   Have you had the soil
tested, adjusted PH if needed?

 In article
 trader4@optonline.net wrote:


  Insect damage was suggested by my lawn service, looked for, none
found, and I believe them since the application of an insecticide would
be an additional expense.
      How would I go about testing pH. Would that have induced the
gradual thinning over a few years?

 
When did they look for insects?  Timing is everything.  You need to
look for them when they are active and actually there.   If you wait
until you notice lots of damage, which could be months later, you may
not find them.



Your lawn service should be testing it, though most of them use hand
held probes which may not be that accurate.  Best way is if there is a
county agricultural extension service or similar in your area.   Here
in NJ I can send in a sample to be tested for about $12, which
includes not only PH, but other key factors too, like NPK, etc.   They
also sell soil test kits at lawn/garden shops or home centers.   I
wouldn't trust it for the other tests, but for PH it should be OK.
Whether PH is a problem depends on how far it's off.  Grass will
tolerate a fairly wide range, but most does best when it's around
6.5.

Regarding the agricultural service idea, usually if you have one of
those you can bring them a sample of cut out turf, incuding intact
soil, roots, etc and they will look at it and see if they spot
anything.

It may be that several things are combining to create the problem.   I
guess of particular concern is the fact that you say you've aerated
and overseeded twice in the last few years and it's gotten worse.
Clearly something is wrong.  Another question is what type of grass
has it been overseeded with?   Was it bluegrass, which will spread, or
a cheap rye grass mix, etc.

 In article
 trader4@optonline.net wrote:


    Three various times over the last two years. Mostly early spring,
although also early fall (late August) last year.


    Bluegrass. That is what they said was the original turf.
Thanks. I'll probably head off and get a soil test kit and see what
happens with the pH before I got tearing up the yard for a trip to the
extension service.