Most lawns should be cut at least 2 inches or higher. Improper watering also contributes to weed invasion. Frequent light watering encourages shallow rooting and promotes weak turf, which becomes susceptible to insect and disease attacks as well as damage from traffic. Frequent light watering also encourages germination and development of weeds at the expense of turfgrasses. A soil probe can be used to monitor soil moisture levels.
Most weeds are opportunistic, filling in voids in turf caused by diseases and insects.
Diseases can be controlled by cultural practices and with fungicides. Chemical weed control Herbicides are chemicals that kill or alter the normal growth of weeds. Herbicides can be further divided into preemergence and postemergence categories. Preemergence herbicides are applied prior to germination and emergence of weeds. These are typically used for controlling annual weeds.