Time for pre-emergent? NYC

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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 http://hcs.osu.edu/Landscape/notes/displaybw.lasso?-database=forums&-table=forumposts&id 03&-search
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 05 Mar 2008 15:27:05 -0500, snipped-for-privacy@mucks.net 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 up.
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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If it's alive now, it's not crabgrass.

FYI, you can't seed right after most pre-emergent crabgrass herbicide applications. There are products you can use while seeding, but I don't know how effective they are.
--
http://NewsReader.Com /

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

you can use corn gluten meal for a preemergent, shouldn't bother cats any.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

And apparently is used as a hog food as well so I guess it is safe for cats. That's one of the best hints I've ever read in usenet. Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 8 Mar 2008 07:55:16 -0800 (PST), snipped-for-privacy@optonline.net 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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

When is that, the fall? :-)
--
http://NewsReader.Com /

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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 and alaninyl-alanine.
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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 11 Mar 2008 10:49:45 -0700 (PDT), snipped-for-privacy@optonline.net 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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.