Light watering causes germination and growth of shallowly rooted weed species. Excess irrigation may lead to infestations by yellow nutsedge and annual bluegrass. Adequate drainage eliminates waterlogging. Compaction of the lawn area due to excessive foot traffic will encourage the invasion of certain weed species. Fescues are the best for shady areas, whereas turf-type perennial ryegrass varieties, which require full sun, establish themselves quickly in newly seeded areas and will crowd out germinating weeds.
Kentucky bluegrass establishes more slowly, but once it is established it is very competitive.
The 2,4-D spray works best in the spring or in September when broadleaf weeds are actively growing. This treatment will generally thin Dutch clover in the lawn. A large number of broadleaf weeds resistant to 2,4-D can be controlled by mecoprop, dichlorprop, and dicamba. A thorough wetting of the leaves with any type of chemical spray is required for effective control. Be careful when using dicamba near shrubs, etc.