There are two types of crabgrass: smooth crabgrass (Digitaria ischamum) and hairy crabgrass (Digitaria sanguinalis). They are both summer annuals that grow quickly and produce an abundance of seeds. The seeds require light to germinate, so keeping your turf thick and dense will go a long way in stopping crabgrass from gaining a foothold. Ridding the turf of a crabgrass infestation requires the use of herbicide, twice during the season. Read the label on the herbicide to see if it is certified for use on Bermuda turf. Failure to do this can result in the death of the turf.
Determine when crabgrass emerges in your region. Call your county cooperative extension office to find out the dates. Make your first application of pre-emergent herbicide just before the crabgrass emerges from the soil.
Mix the herbicide in the tank sprayer at the rate suggested on the herbicide label. Walk the length of the turf, spraying evenly as you walk. Turn and walk in a strip abutting the first pass, again spraying as you walk. Continue this pattern until the entire turf area has been sprayed.
Water the area well after application to help activate the ingredients in the herbicide, unless the label specifies otherwise.
Reapply the herbicide in two weeks using the same procedure.
Wait at least three days after the second application to mow the lawn.
Spray post-emergent herbicide directly on older crabgrass that managed to germinate. Spray the entire plant until it is dripping.