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When to apply crabgrass pre-emergence

Ron D.

LawnSite Member
Location
North Texas
I live in north Texas, have bermuda, and last year had a lot of crabgrass. I spot sprayed last summer with MSMA when temps got above 80 degrees and got very good results, but this year I would like to get a jump on it with a pre-emergence. What is a good granular crabgrass pre-emergence that I could use in my area, and what is the best time to apply? I also have Creeping Charlie, that is even growing well now, that I would like to treat at the same time. I also have the other common weed issues, like dandelions. Will one product take care of everything, or do I need different products?

After applying the granular pre-emergence, I plan on aerating, over seeding with bermuda and then top dressing. I know I need to wait for a certain period of time after applying the weed/crabgrass treatment, but I'm thinking I'll be ok if I apply the treatment toward the end of Feb, beginning of Mar, and then overseed around the middle of April (wait at least 6 wks?).

Any advice is greatly appreciated.
Ron
 

betmr

LawnSite Bronze Member
Location
Piscataway, NJ
Pre-emergent Herbicides and over-seeding do not go well together. Pre-emergents work by hindering germination and affecting young seedlings. I would suggest avoiding pre-emergents if you plan to over-seed, Tolerate what weeds you get, and spot treat. Then use Pre-em's next season.

Any aerating or soil disruption, should be done prior to pre-emergent, so as not to disturb the barrier of chemical.

That's my opinion.
 

jkearnan

LawnSite Member
Location
Visalia, CA
Let me start by saying I AM ONLY A CRAZY HOMEOWNER, not a landscape professional. So take my comments accordingly.

I had a bermuda lawn that was in rough shape relative to weeds....many of the same ones you mention. I went pretty radical and hit the whole thing with RoundUp.

RoundUp, as I understand it, needs an actively growing plant to be effective. The product is picked up by the growing plant, translocated to the roots, where it then works to kill the plant (from the roots up). AS LONG AS your bermuda is still dormant, ie....NOT growing, RoundUp should kill all the current "green" weeds while not damaging your bermuda. This was my theory at least!

I have no idea if this is a normal practice or not. I tried it and maybe just got lucky, but it worked great for me to knock all my weeds back just before my spring growing season started.

I know this was not your question, but since your question dealt with weed control in bermuda I felt I could add my comments.
 

mandmrossi

LawnSite Member
Location
Marietta, Ga
Ron,
I am a homeowner in Georgia, somewhat maybe similiar and have bermuda. I use lesco pre-emerg in Oct & Dec with scott's winterizer in Dec as well, then I hit early feb with scott's with halts and again in early march with scott's with halts. 1/2 acre of lawn and I have had many landscapers ask me how I manage to keep zero weeds, crabgrass etc. from growing and at half the price they can do it for.. lol

Mike
 
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Ron D.

LawnSite Member
Location
North Texas
Thanks for the responses.

Hey Mike, I had just decided to stop by HomeDepot and get the Scott's Halt. I will get it down by this weekend. I think I'll have plenty of time to have this work before I overseed. I will wait to aerate and seed the Bermuda about the first part of May when the temp is getting right for germination.

There seems to be debate about aerating after the treatment as some say it breaks the barrier that keeps the crabgrass from growing. I think if I can stop the initial crabgrass growth before I aerate and seed in early May, then once the seed takes hold it should help keep the crabgrass out. Many professionals here say that a good healthly lawn is the best defense, and I started working on my lawn's health last year. Added lots of compost and a lot of aerating given my heavy clay soil type.

But the weather/season is getting here pretty quick and I need to get things rolling. Thanks again for the responses.

Ron
 

Marcos

LawnSite Gold Member
Location
Cincinnati OH
Any advice is greatly appreciated.
Ron
Ron,

Once you get your turf healthy & dense, the grass itself will do much to prevent potential future germination & encroachment of weeds.

Think Charles Darwin & :cool2:'survival of the fittest' :cool2: whenever you think of turf vs. weeds in your lawn.

I don't know what sort of turf density you've got now because you haven't posted digital pics.
But doing annual smart cultural stuff (maybe 2X annually in TX) like core aeration is a good way to get there, especially in thick stolon-ridden turf like bermuda & zoysia.
And of course, late summer / early fall renovation (or raking, seeding & watering) may be necessary in some of the most troublesome weedy areas you've had in the past.

Sidewalk edges are typically among the worst areas! :cry:
Avoid 'digging' into the soil with edgers or weed-eaters after spring pre-emergent has been applied; do the heavy edging for the season RIGHT NOW!
And try to keep the turf behind these edges as dense as the rest of the turf. :waving:
 

Marcos

LawnSite Gold Member
Location
Cincinnati OH
There seems to be debate about aerating after the treatment as some say it breaks the barrier that keeps the crabgrass from growing. I think if I can stop the initial crabgrass growth before I aerate and seed in early May, then once the seed takes hold it should help keep the crabgrass out. Many professionals here say that a good healthly lawn is the best defense, and I started working on my lawn's health last year. Added lots of compost and a lot of aerating given my heavy clay soil type.
The core aeration & pre-emergent debate has been going on for decades.
Your local professionals are correct; it all boils down to turf density.

Some folks who applied pre-emergent then aerated have break-throughs.
Then they blame the guy with the aerator, but in reality their turf probably wasn't dense enough to fight off the inevitable weed competition to begin with.

Compost is excellent. :)
(I'm saying this knowing full well I may get blasted by somebody 'hard core' from the organic forum :laugh::)
Keep in mind that once you begin to introduce microbes & organic material in the form of compost, meals (etc) you've got to be EXTRA careful not to go over the recommended label rate of box store fertilizer & pesticides.
 
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Ron D.

LawnSite Member
Location
North Texas
Thanks Marcos. I've spent a lot of time reading the organic posts here and it seems many LCO's will use a mixed approach, some organic, some chemical. I have a good start on being organic since last year, when I applied a lot of compost and have used exclusively Milorganite for fert. I didn't overseed my front yard last year because I waited too late, but got good results in my back yard where I lightly disc, heavily aerated, top dressed, re-aerated to mix thoroughly, then seeded and then raked the seed in. Great stand of grass where I've done this, and I will not crabgrass treat this area as my turf is good and will simply aerate, overseed and top dress again.

What's your opinion on just skipping the crabgrass treatment in my front yard all together and just work on the new grass? Last year in front I sprayed the big CG clumps with MSMA and got great results, but I had a lot of immature CG mixed in with the bermuda. My concern without treatment would be last years immature CG getting a banner stand that would choke out the new seed.

Thanks again for advice.
Ron
 
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Ron D.

LawnSite Member
Location
North Texas
Crab Grass is an annual weed. Any plants from last year are dead. New plants will sprout from seeds.
I had no idea it died off every year. Particularly since it kept coming back stronger each year. Given it sprouts from seed, I may not have as bad of situation as I had at the beginning of last year. I killed most of the mature clumps that seed, not all however before some seeded. But I'm leaning toward not treating my front lawn where I've added a lot of organic nutrients, spot treating as you recommend, and using the pre emergent where I haven't done much improvement. I have 1.3 acs and haven't seeded/top dressed the south .40 yet.

That again.
Ron
 
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