Pre-Emergent Program for Cool Season Lawns
Use a split program: Step 1 is granular DG pre-emergent (dispersible granule breaks into 1000s of sub-particles). Step 2 is spray pre-emergent which also has POST-emergent killing effect on young crabgrass that broke through Step 1. Spring timing: apply when soil temp reaches 55°F at 4-inch depth for 3-5 consecutive days, ideally 2 weeks early. Use greencastonline.com or a soil thermometer — calendar dates vary by 2-4 weeks depending on year. Fall timing: apply when soil temp drops below 70°F at 4-inch depth. IMPORTANT: Do NOT apply pre-emergent if you plan to seed.
Frequently Asked Questions
When should I apply pre-emergent?
Apply before soil temperatures reach 55 degrees F at 4-inch depth. The product needs time to activate and form a barrier before crabgrass germinates. A split application with two half-rate apps 6-8 weeks apart extends coverage.
Can I seed and apply pre-emergent at the same time?
No. Pre-emergent herbicides prevent all seeds from germinating, including grass seed. Wait at least 8-12 weeks after pre-emergent before seeding, or seed first and skip pre-emergent in that area.
What is a split application?
Instead of one full-rate application, you apply half the rate in early spring and the other half 6-8 weeks later. This extends the pre-emergent barrier through the entire germination window.
What if I missed the pre-emergent window?
If crabgrass has already germinated, switch to a post-emergent product like quinclorac. Pre-emergent only prevents germination and will not kill existing weeds.
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