The best defense against weed growth is a competitive, healthy turfgrass. Weeds are opportunistic plants that thrive in low fertility soil and shady lawn environments. Sparse or thin areas of grass are highly susceptible to weed infestation. Minimizing weeds in your lawn is best accomplished by optimizing the lawn environment which includes proper mowing, watering, fertilizing and aerating of the turfgrass.
As a general rule, mowing at a higher level is better than mowing at a lower level. Think of the grass' top growth as a direct reflection of the grass' root depth. The deeper the root system, the healthier the turfgrass and the less likely weeds will successfully compete. Ideal grass height varies with individual species; however, 2 to 3 inches is a good rule of thumb. Always mow the lawn with a sharp cutting blade and never cut more than 1/3 of the top growth at one time.
Light, frequent watering targets shallow root systems, supporting the growth of lawn weeds The best method of irrigation involves periodic, heavy watering of the topsoil, which supports the grass' deeper root systems. Based on your climate and type of lawn grass, determine the ideal amount of watering on a weekly basis. Water the grass to the recommended weekly levels, taking into account natural rainfall, using the infrequent, heavy irrigation technique.
Applying too much fertilizer provides food for weeds and applying too little fertilizer damages grass health, allowing weeds the competitive advantage. In general, all types of lawns will benefit from an annual fertilizer application in mid-summer when grass growth is most rapid. When applying fertilizer to an established lawn, use no more than 1 lb. of nitrogen-based fertilizer per 1,000 square feet.
Highly trafficked lawn environments are susceptible to soil compaction. Soil compaction restricts the flow of minerals and water through the topsoil, causing top growth to become sparse, again opening the door to weed infestation. Aeration is the puncturing of holes into the topsoil and is an effective method of alleviating soil compaction problems. Aerate the lawn only when the grass is actively growing. Use a mechanical core aerator to makes several passes over the lawn. Leave the plugs or cores on the lawn after aeration, as they serve as a natural fertilizer.