Summer Crab Grass Control And Bluegrass Lawns

Question: Every summer our bluegrass lawn gets “infested” with crab grass, what can we do to get some control of this weed pest? Katie, Dyersburg, Tennessee

Answer: Katie, where crabgrass is present, watering should be avoided as long as possible. Frequent and light waterings are especially undesirable, since they do the permanent grasses little or no good, yet encourage crabgrass to spread rapidly. Keeping the mower blade set 1-1/2 inches or higher in hot weather prevents crabgrass runners from spreading and rooting so rapidly. Crabgrass cannot be cut close enough to stop it front setting seed.

Chemical preparations are useful for crabgrass control if properly applied. Instructions on the container for rate and frequency of application should be followed to avoid serious turf injury. Trial applications on an inconspicuous corner of the lawn give the home owner experience in chemical treatment and determine whether the amount of injury is tolerable.

The best season for applying and crabgrass killer preparations is from late July through mid-August.

The use of chemicals for crabgrass control is not justified unless the permanent turf grasses are improved by regular fertilization and higher mowing. For the Kentucky bluegrass-fescue lawn the height of cut may be kept at 2 inches until crabgrass is brought under control, then lowered to 1-1/2 inches, Crabgrass cannot be eliminated entirely in one year. All plants should be kept from producing seed for a period of several years. Even then it is better to keep the occasional plant from going to seed than to run the risk of a future infestation.

Dandelions, buckhorn and broadleaved plantain are readily destroyed by 2,4-D preparations. Applied according to the instructions, a small quantity of this chemical can destroy a surprising number of weeds. This chemical, and the sprayer used for it, should be kept away from other valuable garden plants since it may damage them. And if late summer or fall reseeding is planned, make the final treatment several weeks before.