As a chemical-free alternative, though it still uses gas, Lanini recommends torching weeds with small landscape flamers, which are hooked to standard propane tanks. He said this method is quick and effective for ridding weeds in sidewalk cracks and lawn edging.
“There is a real satisfaction in turning them to charcoal,” However, he said flames kill weeds long before the weeds are reduced to ash. He suggests pinching the weed leaf with a thumb and forefinger. If it leaves a fingerprint, the weed is dead.