Salt Formula for Killing Weeds
Historical Use of Salt
- The use of salt to destroy unwanted plants is not a recent strategy but has been known and practiced since ancient times, cites the Purdue University Extension. Salt produces an indiscriminate damaging effect on all plants, including weeds. This toxicity of sodium chloride was a biological warfare strategy used by ancient armies to destroy enemy fields and crops.
- Salt is available by particle size according to intended use. Rock salt, with its coarse structure, has the consistency of loose gravel. Table salt, on the other hand, has a fine consistency with minute granules. Kosher salt is somewhat flaky in structure but coarse with compressed pellets. Kosher salt is often used to soften water. The salt used for deicing roads is a mixture of salt, sand and other minerals. All types of salts kill plants and weeds.
Effect of Salt
- As salt dissolves in water, the sodium and chloride ions separate. The sodium ions replace the other nutrients in the soil, making them unavailable to plants and weeds. The chloride ions are absorbed by the roots and collect in the growing points of the plants, gradually assuming toxic levels. Plants start to reveal drought-like symptoms, wilt and slowly die.
- Apply high concentrations of salt to weed roots and water it in to kill weeds from the roots. Don't dissolve the salt in water first. The recommended rate is about 1 cup for 10 square feet, reports Jeff Gillman and Michael A. Dirr in "The Truth About Garden Remedies." Avoid dumping salt randomly, as it will kill both desired and undesired plants.