How to prevent crabgrass: For problem areas, use an organic or synthetic pre-emergent herbicide, such as Espoma Organic Weed Preventer (organic) and Barricade Professional-Grade Pre-Emergent Weed Control (synthetic). These chemicals are designed to kill seedlings before they establish a root system. To be effective, pre-emergent herbicides must be applied before crabgrass seeds germinate, when soil surface temperatures reach 50 to 60 degrees Fahrenheit. One way to time this application is to apply pre-emergent herbicide when you see the first forsythia begin to bloom. Important note: pre-emergent herbicides also prevent grass seeds from germinating, so you cannot use these products where you plan to seed grass. The best weed killers for henbit: For a safe-to-use mineral herbicide, look for iron-based products such as Bonide Weed Beater FE and Natria Lawn Weed & Disease Control. Apply to young, actively growing weeds in the spring or fall when temperatures are cool. Treatments should be reapplied three to four weeks after the first application for optimal control. How to prevent dandelions: Dandelions thrive in thin, sparse lawns. Regular overseeding and other steps to maintaining a dense lawn reduces seed germination. Leaving grass clippings in place also helps, while benefiting your lawn. Both the iron-based herbicides and pre-emergent products listed above also work for dandelion control. The best weed killer for nutsedge: For large infestations, chemical control may be necessary. Nutsedge requires the use of very specific herbicides, such as Ortho Nutsedge Killer for Lawns, to achieve satisfactory control. Normally, two applications are required 10 to 14 days apart. When applying control products, avoid mowing three to five days before and after treatment and do not water for at least 24 to 48 hours after application. Begin chemical control in the late spring or early summer when nutsedge is young, actively growing, and most sensitive to herbicide. How to prevent creeping Charlie: Overseed cool-season grasses as necessary to maintain a dense turf. Iron-based weed killers can also be effective at managing creeping Charlie. The best weed killers for shepherd’s purse: The iron-based herbicides listed above are labeled for use against shepherd’s purse, as is Barricade Professional-Grade Pre-Emergent Weed Control. Applications of Barricade should be made in late summer, fall, or winter to prevent seed germination of this cool-season weed. The best weed killers for quackgrass: The pre-emergent herbicides listed above can also be applied in early spring to prevent seedlings from establishing. Remember that pre-emergent herbicides cannot be used in conjunction with overseeding. The best weed killer for broadleaf plantain: If problems persist, apply an iron-based herbicide to manage remaining broadleaf plantain weeds. The best weed killer for chickweed: Since the window for weed control is so short, applying a pre-emergent herbicide such as Barricade Professional-Grade Pre-Emergent Weed Control in late fall or early winter is among the more effective control measures. For established plants, the iron-based herbicides listed above can be applied. The best weed killers for common knotweed: Where chemical control is necessary, the iron-based herbicides listed above are effective against young knotweed plants. Barricade Professional-Grade Pre-Emergent Weed Control can be applied in late winter or early spring before knotweed seeds germinate to prevent them from establishing.
