Fast Action Roundup Ready to Use Weedkiller is a systemic weedkiller that kills weeds from the inside out. This pump n go enables you to pump and spray for 3 minutes, making application easier. Fast Action Roundup attacks the roots to stop weeds returning. The fast acting formula gives results in 1 - 2 days. It also fully degrades in soil to allow replanting. Use Fast Action Roundup Pump n Go Ready to Use Weedkiller from February to November. Fast Action Roundup Pump n Go Ready to Use Weedkiller 5L will treat up to 150m