TL;DR
A pre-emergent herbicide is a soil-applied product that forms a chemical barrier in the top inch of ground, stopping weed seeds—crabgrass above all—as they germinate, before any plant is visible. Active ingredients such as prodiamine and dithiopyr must be watered in and timed to soil temperature, traditionally when it holds around 55 degrees Fahrenheit in spring.
What it means
A pre-emergent herbicide is a soil-applied product that forms a chemical barrier in the top inch of ground, stopping weed seeds—crabgrass above all—as they germinate, before any plant is visible. Active ingredients such as prodiamine and dithiopyr must be watered in and timed to soil temperature, traditionally when it holds around 55 degrees Fahrenheit in spring. It does nothing to weeds already up, and seeding new grass must wait until the barrier degrades.
Where it sits in the glossary
Pre-emergent herbicide is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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