{"id":36914,"date":"2025-03-07T13:39:44","date_gmt":"2025-03-07T13:39:44","guid":{"rendered":"https:\/\/lawnlove.com\/blog\/?p=36914"},"modified":"2026-08-07T23:45:44","modified_gmt":"2026-08-07T23:45:44","slug":"when-to-apply-pre-emergent-herbicide","status":"publish","type":"post","link":"https:\/\/lawnlove.com\/blog\/when-to-apply-pre-emergent-herbicide\/","title":{"rendered":"When to Apply Pre-Emergent Herbicides"},"content":{"rendered":"
Key Takeaways<\/strong><\/th><\/tr><\/thead>
\u2022 Apply spring pre-emergent when soil temperatures consistently reach 55\u00b0F.
\u2022 Apply fall pre-emergent when soil temperatures drop to 70\u00b0F.
\u2022 Most pre-emergents last 8-12 weeks, so 2 applications per year (spring and fall) provide season-long protection.
\u2022 Timing varies by region: Southern states apply in February for spring and late September-October for fall; Northern states apply in April for spring and August for fall.
\u2022 Never apply pre-emergent to new grass seed\u2014it prevents all seeds from germinating.<\/td><\/tr><\/tbody><\/table><\/figure>

Apply pre-emergent herbicides in spring when soil temperatures reach 55\u00b0F (typically February-April) to prevent summer weeds like crabgrass. Apply again in fall when soil temps drop to 70\u00b0F (August-October) to stop winter weeds. Timing varies by location\u2014Southern homeowners should apply earlier than Northern regions.<\/p>

Pre-emergent herbicides create a barrier in soil that stops weed seeds from germinating. Missing the application window means weeds establish roots before the herbicide can work. If you’re short on time, Lawn Love’s local lawn care pros<\/a> handle pre-emergent applications with precision timing and professional-grade products.<\/p>

Spring pre-emergent application<\/strong><\/span><\/h2>
\"graphic
Infographic by Juan Rodriguez<\/figcaption><\/figure>

When to apply in spring<\/strong><\/span><\/h3>

Apply spring pre-emergent when soil temperatures consistently reach 55\u00b0F for several consecutive days<\/strong>. Use a soil thermometer inserted 1-2 inches deep (even a meat thermometer works). This temperature triggers summer annual weed germination, so you need the barrier in place beforehand.<\/p>

Most pre-emergents last 8-12 weeks, giving you flexibility in your application window. “Apply your spring preemergence herbicide when soil temperatures reach approximately 55 degrees for several days,” says Becky Grubbs, turfgrass specialist at Texas A&M University AgriLife Extension.<\/p>

Spring application by region<\/strong><\/span><\/h3>