Jonathan Green Season-Long Weed PreventerJonathan Green Season Long Weed Preventer for lawns and landscapes contains Dimension, a clear and odorless chemical that kills and prevents crabgrass both before and after it germinates up to the 3rd leaf stage. At maturity crabgrass is a 7 leaf plant. Dimension also stops more than 30 other grassy and broadleaf weeds from invading the lawn and garden beds if applied before the weeds germinate. The weed control lasts for the entire growing season.