How to prevent and control spring weeds?

If you need to seed bare patches or overseed thin areas in spring, do not apply pre-emergent herbicide to those areas. Pre-emergent kills all germinating seeds, including grass seed.

Raise your mowing height to the upper end of the recommended range for your grass type. For cool-season grasses, this means 3.5 to 4 inches; for warm-season types, the top of their range.

Instead of one full-rate application, split your pre-emergent into two half-rate applications spaced 8-10 weeks apart. Apply the first at the standard soil-temperature trigger and the second in late spring or early summer.

Focus on building a dense, vigorous lawn through proper mowing height, appropriate fertilization, and correct watering. A thick lawn is the single most effective weed suppression strategy.

For small infestations, pull weeds by hand after a rain when the soil is moist. Grip the weed at the base and pull slowly to extract the entire root. Focus on removing weeds before they flower and produce seeds.

Once broadleaf weeds like dandelions, clover, and plantain are actively growing in spring, spot-spray them with a 2,4-D based post-emergent herbicide. Apply when daytime temps are between 60-85°F and no rain is expected for 24 hours.

Spread corn gluten meal at 20 lbs per 1,000 sq ft in mid-spring, timed to coincide with when you would apply synthetic pre-emergent (soil at 55°F).

Apply dithiopyr (sold as Dimension) in mid-spring. Unlike most pre-emergents, Dimension also provides early post-emergent control on crabgrass that has already germinated up to the 1-tiller stage.

Apply prodiamine (sold as Barricade) at the label rate in mid-spring. It provides the longest residual control of any pre-emergent herbicide — up to 6 months at full rate.

Monitor soil temperature at 4-inch depth. When it reaches 55°F for 3 consecutive days, apply a pre-emergent herbicide. This is the threshold at which crabgrass and other annual grassy weeds begin germinating.