Doff 24/7 Superfast Weedkiller is a ready to use non-selective weedkiller spray with pure contact action on all green plant parts using pelargonic acid as its active ingredient. This weedkiller spray is designed for spot weed treatment on all common garden weeds growing on patios, paths and borders. Results are usually visible within 24 hours as a significant withering and browning of the leaves. For best results it is recommended to apply small actively growing weeds. Application may. need to be repeated at 2-4 week intervals.