How Long Does It Take for Salt to Kill a Weed?

Salt works as an effective weed killer by dehydrating the root system and stopping the roots from absorbing necessary nutrients. Small doses of salt aren't likely to hurt large plants and shrubs immediately, although continued doses over time will do so. On small plants with shallow root systems such as many weeds, however, salt's killing ability works fast.

Applying Salt

Salt works as a weed killer when it dissolves into the soil around the plant roots. When you pour salt by itself around the base of a weed, it could take days for the salt to dissolve from the soil's moisture or to wait for a rainy day to help the salt soak in. There's a faster way to apply the solution and kill the weed, though. Mix 1 cup of salt in 2 cups of boiling water and pour it over the offensive weed. The boiling water burns the leaves and causes them to wilt while it helps the salt dissolve immediately into the soil around the roots. It still takes a couple of days for the salt to dehydrate the roots enough to kill most weeds, but it helps when the weeds are already damaged by the boiling water. Salt can kill plants indiscriminately and stays in the soil for years, so use it only where you don't want other plants to grow, such as driveway cracks.

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Shala Munroe


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