Crab Grass Preventers

[JDGREEN4ME]

Do any of those preventers (Scott's, etc.) help control crab grass? Do you mow and/or dethatch prior to application?

 

[Bird]

Last year I used Ortho® Weed-B-Gon® Crabgrass Killer For Lawns Concentrate for the first time and had better luck with it than anything else I've ever tried. I bought it at The Home Depot. Of course, it's a spray that you apply directly to the crabgrass and dalisgrass and it does take a few days before you see the effect.

 

[DocHeb]

You should do all your dethatching and core aerating before spreading the crabgrass preventatives. The active ingrediate coats the ground and prevents seed germination. Dethatching and core aerating after this chemical coating occurs decreases the effectiveness as it opens up soil that hasn't been coated.

 

[beenthere]

I think I have had good luck over the years broadcasting crabgrass preventer, but the timing is critical up to a point. The directions vary from "apply the first period of three warm days over 70°" to "apply after the forth mowing". I find that I get little to no crabgrass where I apply it and crabgrass where I do not apply it. That is over about half of my 8 acres. Certain areas there doesn't seem to be a crabgrass problem at all.
I only have applied the pre-emergent variety, and not the liquid.

 

[DocHeb]

Around here the Mother Nature timetable is to apply the crabgrass pre-emergents when the Forsythia bloom.

 

[beenthere]

DocHeb
I've heard that too, as well as when the lilacs bloom. I've had a lilac bush in the yard for 25 years and it has never bloomed yet.
Kids bought us a new one last year and we'll see if it will bloom this year /forums/images/graemlins/tongue.gif /forums/images/graemlins/grin.gif

 

[gsxr1100]

yup, heard that since I worked at Agway. I go by Forsythia but that is me.

I rake or “broom” the grass, aerate or plug and then put the goo on!

 

[anthonyk]

Anything work on Bermuda?
Most of the ones I've seen said for use on Augustine only.

anthony

 

[johan3400]

There is a difference in active ingredients and when to apply for the best control. Most of the chemicals will not have much post emerge control. The two most common are Pendimethalin and dimmension. The dimmension has good control even if the weed grasses are into the two leaf stage. In northern Illinios and Iowa we can put dimmension products down until the first part of may. The chemicals typically last 8 weeks and as others have said you do not want to disturb the soil after you treat. Grannual programs work well and spray works well too.