Apply Crabgrass Preventer Now!

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Crabgrass can sprout as early as April 10 in Fairfield County. Have your preventative herbicide in the soil before it does!

March through early April is the perfect time to apply "crabgrass preventer" in home lawns. Crabgrass is probably the most hated grassy weed in home lawns.  Fortunately, it is an annual weed and can still be controlled for the coming year.  Annual grass weeds germinate from seed, grow vegetatively, produce seed and die within a 12 month period.  In addition to crabgrass, there are a number of other annual grass weeds, such as goosegrass, foxtail, barnyardgrass, fall pancium and annual bluegrass.  Crabgrass and other annual grass weed normally begin to germinate around April 10 in central Ohio.
 
To ensure crabgrass and other annual grass weeds do not establish in home lawns, both preventive and control programs must be implemented.  The invasion of crabgrass and other annual grass weeds can be prevented to a large degree by maintaining a dense, healthy stand of grass.  A high quality lawn will develop a highly competitive canopy which will shade the soil surface and discourage the germination and establishment of seedling annual grass weeds.
 
In the absence of a dense, healthy lawn, the best way to stop crabgrass and other annual grass weeds from establishing in lawns is through the use of pre-emergent herbicides.  Pre-emergent herbicides are chemicals that prevent the germinating weeds from establishing in the lawn.  These herbicides control annual grass weeds by inhibiting cell division in the young root system.  The failure of the root system to develop results in the death of the young seedling weed shortly after germination.  Lawns with thin stands of grass that do not provide 100% cover may require yearly applications of a pre-emergent herbicide to prevent the invasion of crabgrass and other annual grass weeds.
 
The great majority of the products labeled for crabgrass control will provide good to excellent control, if applied between March 1 to April 1.  One word of caution, do not applied pre-emergent herbicide (unless the active ingredient is Siduron) if you were planning on re-seeding portions of the lawn.  Siduron is the only herbicide that will provide control of the annual grass weeds but not injure or antagonize the development of the desirable seedling turfgrasses.  Siduron may be applied at the time of seeding.
 
Pre-emergent herbicides are generally only effective if applied before the annual grass weeds emerge. Therefore, early spring applications are essential if satisfactory weed control is to be achieved.  Herbicide applications should be completed and the herbicide watered or rained in at least 7 days prior to the initial germination date to allow time for the herbicide barrier to be established in the soil.  Pre-emergent herbicide applications for annual bluegrass control should be made in late summer or early fall.
 
Find more details on crabgrass control in OSU Extension fact sheet: HYG-4002, Annual Grass Weed Control in Home Lawns or watch the new podcast entitled Crabgrass Emergence & Control by OSU's Dr. John Street.
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