I'm always too late for pre-emergent so this year I'm trying harder.
New York City, mostly concerned with dandelions, crabgrass, and
clover. Since I let my cats into the yard, I'd like to put something
down that will not harm them. I figure I can keep them inside for a
week or so to give the poison time to dissipate. Does it work like
that? If not, I guess I'm stuck with the weeds. Thanks.
Pre-emergent herbicide is a must for crabgrass but is not a must for
other weeds. Other weeds can be controlled without precise timing.
The timing for using pre-emergent herbicide for crabgrass is best
indicated by the Forsythia's bloom withering.
I would think that the date would be around the first week in April.
See this page for further details
On Wed, 05 Mar 2008 15:27:05 -0500, email@example.com wrote:
Ah, so I need to do this two weeks before the daffodils bloom withers.
I don't know of Forsythia near my house but since 9/11 some Dutch
company has been flooding NYC with free daffodil bulbs so the whole
area has daffodils planted. I noticed last week that they were coming
So another few weeks and I get to nail the crabgrass at least. That
will take out about half my lawn I guess. I really lost the battle
last year.I'll be seeding quite a bit.
Per the advice on pre-emergents being incompatible with seeding, I'd
check out the corn gluten as well, as I would suspect that will
prevent germination of grass seed too. That's one reason why I always
do seeding in the Fall, unless it's impossible for some reason. If
you need to seed, you can use Tupersan as a pre-emergent. However, it
is considerably more expensive than the std pre-emergents. And the
cost of the corn gluten is probably the most expensive of all.
Regarding timing, here in NJ I apply mine when the Forsythias bloom,
which is latter part of April. You don't want to get it down too
early, as it has a limited span and crabgrass doesn't germinate until
warm temps arrive.
Regarding pet safety, that's a tougher call. I would think allowing
pets back on after a week may not make much difference. These
products work by remaining at the soil surface for many weeks, which
is how they are effective at blocking germination. Also, you can
limit the areas where you put down pre-emergent. Crabgrass won't
grow in any shady areas, so you can skip those, which may help.
The final option is to not use a pre-emergent at all and spot treat at
the first sign of any crabgrass with Acclaim.
On Sat, 8 Mar 2008 07:55:16 -0800 (PST), firstname.lastname@example.org wrote:
Thanks. My major problems are crabgrass and clover. Clover, I
understand, is not really a problem but is beneficial. Still, there
are areas where it is overpowering the regular grass. Pre-emergents
aren't going to take care of clover anyway.
Expense isn't a major factor; the whole lawn is around 500 sq feet. I
think I try the corn gluten, which I'm sure won't hurt the cats. Then,
after a few weeks, I'll throw down some more grass seed, after the
threat of crab grass diminishes.
Agree. That's obviously the next seeding time after applying pre-
emergent in the Spring. To be effective, the pre-emergents have to
last many weeks. And you don't want to be seeding in July.
He could use Tupersan, or similar pre-emergent that is compatible with
new seeding. But even then, I'd do the seeding FIRST. You want the
new grass to get going ASAP, so it gets established before hot
weather, where heavy watering, weeds, etc become a problem. Grass
germinates in the 50's, long before crabgrass.
Ha Ha, but still, a good question. I figured that if a pre-emergent
works on crabgrass but not regular grass, and must, by definition, be
used before crabgrass emerges, then after a certain time interval it
will be safe to stop using it and I can seed regular grass.
From what I read, corn gluten meal works on a physical level by
draining moisture from seeds and cracking them open. Hopefully that
will affect the crabgrass. Then, once the crabgrass seeds are all
desiccated and cracked, I can put down some regular grass seed and
hope for the best.
What you read is pure BS. If it worked by draining moisture, what
would happen if it's rainy and damp for a couple of weeks? You'd
have crabgrass and weeds all over the place.
The explanation I found below makes a lot more sense:
"What makes it work?Once it was determined that corn gluten meal
contained a natural compound or compounds that could inhibit weed
establishment, the next logical step was to determine the nature of
that compound. Graduate student Dianna Liu began this work in 1989.
Liu eventually determined that five individual dipeptides
(combinations of two amino acids) had the ability to inhibit root
formation of germinating seedlings. These dipeptides were glutaminyl-
glutamine, glycinyl-alanine, alaninyl-glutamine, alaninyl-asparagine
ReferencesChristians, N.E. 1993. "The use of corn gluten meal as a
natural preemergence weed control in turf." International Turfgrass
Society Journal 7: 284-290."
And whatever makes it work, it appearntly works for 4-6 weeks. That
means if you apply it at the right time, it's going to be there into
June in NYC. If you start seeding with grass after that, you're in
summer and you're bound for lots of trouble and likely failure. At
the very least, you better have an effective way of applying water and
lots of it through the summer. I'd just wait till Fall which is by
far the best time to seed.
On Tue, 11 Mar 2008 10:49:45 -0700 (PDT), email@example.com wrote:
Screwed for another year. I did seed in the fall but none of it seems
to have weathered the winter (such as it was) very well. This grass
growing thing is harder than I would have thought. I'm good with
clover though; I think that means I need more nitrogen. Clover is sort
of nice though. The bees love it.
Something is digging holes in the yard. Not burrows, just around six
or eight inches deep. A lot of them. I think it's squirrels. Could be
a raccoon but we don't have many of those around. Could be a oPossum.
Those are around. Maybe it's time to put in a nice rock garden, a
little waterfall, some assorted elves and flamingos. Put nice flowers
where the tomato plants always die, and put the tomato plants where
the lawn used to be. Arrgh.
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