Sir Topham Hatt wrote:
As suggested I would kill the crabgrass with liquid CG killer. At the end of
August, early September, I would core aerate, top dress with compost. Wait 2
weeks after the aeration, then overseed.

"Guitarist511" wrote:

Since it is Aug already and hot here in NJ, what can I do now to stop
the weeds and crab grass. I did the Scotts steps but seem to have had
some bad luck this year. My front is about 5% crab grass and the back
is about 50/50 with grass to weeds. Also, when is the correct time to
overseed and can I get the back yard back into shape over the next
couple of years by overseeding?

Thanks


If you are applying fertilizer to cool season grasses in summer, as per
the Scotts program, you are asking for trouble. Nitrogen, hot temps,
humidity, and water are a prescription for fungus and disease.
Generally, one application of fertilizer plus pre-emergent control in
Spring is all you want till Sept. In NJ, that should go down about mid
April.

As to what you have now, it's questionable what to do about the
crabgrass. You can kill it, but it's not going to be easy now, as the
plants are fairly large. A month ago, it would have been much easier.
If you want to kill it, I recommend Acclaim, which is very effective.
For the other weeds, use a broadleaf weedkiller, like Weed B Gone.
Don't apply either when it's going to be 85 or above, or when the grass
is stressed due to lack of water, etc. Unfortunately, again, current
conditions aren't favorable.

Sept is the ideal time to seed. Depending on how big of a mess you
have and whether you have undesirable grass present, eg coarse rough
stalk grass, disease prone grass, etc, you may want to kill the whole
thing and reseed. To do that, use Roundup in late Aug, then reseed
about 10 days later, using an appropriate and high quality seed. Get
the soil tested and adjust the PH as needed.

For an established lawn, you should fertilize twice in Fall, once in
early Sept, again in mid to late Oct. And don't overwater. More lawns
have probably been killed by overwatering than by lack of water. The
lawn should be watered every 4-7 days, depending on soil and temp. You
want to give it a deep watering, not shallow infrequent. I'd go with
about 3/4" at a time.