My Lawn Has Weeds

Appropriate Turf

• All turfgrass varieties are not the same; each varies in its ability to tolerate wear and tear, extreme hot and cold, shade, or drought. Lawns should be planted with grass that is known to do well in that region; grasses planted outside their adaptability can easily succumb to weed invasions. If the lawn is currently planted with a species that is doing poorly, it may be beneficial to reseed with a tolerant variety, or start the lawn over from scratch to get rid of weeds and the improper turfgrass.

Irrigation

• When lawns are watered improperly, it can weaken turfgrass and allow weeds to take control; nutsedge, bluegrass, crabgrass and dallisgrass are several varieties that thrive in poorly-irrigated lawns. Lawns should be watered uniformly with a sprinkler that is working properly. Watering should be deep and infrequent. Allowing the top 1 to 2 inches of soil to dry out between watering is also recommended. Light watering done with more frequency cause shallow root growth, giving weeds an advantage, especially weeds -- such as crabgrass -- that thrive in these types of moisture conditions.

Aeration

• Heavy activity on turfgrass compacts the soil, prohibiting a proper flow of water, nutrients and oxygen to grass roots. Likewise, a thick layer of thatch -- organic matter such as grass clippings that settles down between the grass stalks -- can create the same problems; slow grass growth and susceptibility to weeds. Soils should be aerated several times a year during the growth season when soil is a heavy clay or receives a lot of foot or equipment traffic. Less active lawns, or those with less-dense soils, should only need a once a year aeration. Aeration involves using a tool to punch holes in or remove small cores of soil from the lawn; this allows oxygen, water and nutrients to flow directly into the ground and reach the grass roots.

Herbicides

• Herbicides can be pre-emergent -- killing weeds before they even show up; or post-emergent -- killing them after they are out of the ground. It is important to know what type of weed you need to kill; some respond to fall applications -- others in the spring or early summer. It is also important to note that post-emergent herbicides do not stop the germination of any seeds; rather, they only kill weeds on contact.