As winter nears its end, temperatures begin to rise, and new growth begins to emerge from its winter dormancy. But instead of turf, some of that growth may actually be unwelcome weeds. To prevent the appearance of summer annual weeds in springtime, be proactive and apply a pre-emergent herbicide in late winter.
Pre-emergent herbicides are an important tool for controlling weeds. For a successful application, focus on thorough coverage, mixing solutions correctly, and timing applications effectively.
Pre-emergent herbicides can be applied in either liquid or water-based granular form. They control weeds before they germinate by creating a chemical barrier just below the soil surface. Thorough, even coverage is key to making this barrier effective, because germinating weeds will die if they cannot breach it.
Pre-emergent herbicides should be watered into the soil during or after the application, so the product can reach weed seeds. Most products call for 0.5 inches of water within 20 to 30 days after application. Granular pre-emergents should be applied at 5-6 pounds per 1,000 square feet, and also require watering into the soil.
Correctly mixing a product is necessary for spray solutions to be at the appropriate strength. Most manufacturer instructions will indicate how much product to use per 1,000 square feet or per acre. These measurements determine how much solution to use for each gallon of water. Always check the product label before making applications, and make sure your sprayer is properly calibrated.
To show where applications have been made, a colorant may be added as a temporary indicator. The colorant is biodegradable, and will usually break down and fade out within 30 days.
Rising temps mean it’s time to act. Summer annual weeds begin germinating when soil temperatures consistently reach 55 degrees at a depth of 4 inches. Different weeds will germinate at different temperatures, so it’s important to apply pre-emergents at the first opportunity.
For effective weed control, make pre-emergent applications twice a year. A rule of thumb is usually around February or March, and again in August or September.
To control summer annual weeds like crabgrass, foxtail, or goosegrass, recommended products include dithiopyr (Dimension®), prodiamine (Barricade®) and pendimethalin (Pre-M®).
Your local Ewing turf experts can help you with determining the right product and application for your needs. Interested in learning more? Visit your local Ewing branch and find the solutions you’re looking for.