On Sep 2, 10:12*am, dpb wrote:
On 9/2/2011 8:49 AM, Rebel1 wrote:

Those are my two choices before overseeding my 12,000 sq ft lawn in
central NJ. Few companies offer dethatching, but I'm not sure if that's
for their convenience or because aerating is really the best way to go.
I would describe the lawn as good; not the best or the worst in the
neighborhood. Soil is loam. Problems are bare spots, clover, crabgrass
and a few misc weeks. I keep after the dandelions, so they are under
control.

Regarding aerating: The seeds that fall into the holes are about 1.5
inches below the soil surface, far below the fraction of an inch seed
companies recommend. While these seeds won't have any soil covering
them, will they still germinate properly? And if they do, when fully
established will the grass from the seeds in the holes look different
from the surrounding grass?

Neither is "better" than the other; they're two different operations to
take curative action against two different problems. *Which your lawn
needs (if either) is indeterminate from the information given.

All in all, the action outlined above isn't likely to solve the actual
problems in the lawn long-term as it's treating a symptom rather than
looking at the root cause(s) for the specific issues.

As example, of specific issues mentioned--clover is symptomatic of
low-nitrogen soils; it's a legume (means it sets N) and is in fact very
beneficial in low-N soils. *As N builds up over several years you'll
find it will gradually fade in abundance relative to the grasses and
you'll get an automagic improvement at the cost of simply some patience,
not dollars.

Bare spots may be showing locations where there are other specific soil
problems such as rock under the surface, clay deposits or simply thin
topsoil left after the lot was prepared. *Simply throwing more seed down
without determining the reason existing didn't make it in those
locations is a highly risky business in terms of the likelihood of the
monies spent actually providing the desired results.

Start w/ a good soil analysis concentrating on the problem areas; w/o
that all else is futile. *Follow-up by contacting local ag county agent
office; even most urban areas have such that have advice and
information/guidance customized to local conditions.

--


Agree with the above excellent advice. You de-thatch if
you have excessive thatch. That can be determined by
lifting a section of turf and looking at the edges. Thatch
is the layer of dead grass material near the surface.
It's normal to have up to about 1/2" or so. It only
becomes a problem when it's so thick it prevents
water and nutrients from getting into the soil. In that
case, it acts like a thatch roof.

You aerate to reduce soil compaction.

If those problems don't exist, then I would rent a
slit seeder, also called an overseeder. Basicly
it cuts grooves of selectable depth and drops
seed. It will cause less damage to the existing
turf than either de-thatching or core aeration.
Local tool rentals or HomeDepot have them.