Weedol Path & Gravel Control Concentrate 12 Tube Weedol® Path & Gravel Weed Control Concentrate Tubes are a pre-mixed concentrate weedkiller that is ideal for use on gravel paths, permeable patios and driveways. Once sprayed, the active ingredient pelargonic acid starts working immediately giving you results in 3 hours and breaks down in soil naturally - leaving the area ready for replanting in just 3 days. The easy dose concentrated formula makes it convenient for treating large areas and saves plastic. Just snap the tube, add water, mix and spray.