The best weed control is a healthy, well-managed lawn. The premise for this statement is that a healthy dense turf canopy provides a competitive edge over weeds. Weeds are opportunist. They germinate and grow where the turf becomes sparse. Generally the reason a lawn's turf canopy becomes sparse is because of other turf management problems. Often the type of weeds present can be used to help identify these problems.
Goose grass and path rush are two common weeds that are found where soils have become heavily compacted. Sedges and kyllinga normally are found on poorly drained areas and algae are often associated with excessive surface water.
For most turf species, soil pH levels need to be only slightly acid, but when the pH becomes too low for healthy turf, oxalis (wood sorrel) may encroach and the plantains generally appear on higher pH soils. Legumes such as clover and lespedeza can be indicators of low nitrogen fertility.
Take note of the type of weeds found in your lawn and maybe some alterations in cultural practices will be the remedy with less dependency on herbicides.
Published June 6, 2011
Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. email@example.com