How Much Salt Will Kill Growing Seeds?

About Salts

• Sodium chloride is the type of salt found in the ocean and used to flavor foods. There are other salts present in desert and semi-desert areas, including sulfates, carbonates, and bicarbonates of calcium, magnesium and potassium. The salinity of the water in arid areas is caused by the combined presence of these salts. Salinity is measured by how well it conducts electricity, in values called Electrical Conductivity (EC) units.

The Effects of Salt on Plants

• Sodium chloride attracts water and, for instance, can clog the holes of a salt shaker in humid environments. It also attracts water in the soil, preventing roots from getting the moisture they need at higher concentrations.

  Salt separates into two ions when dissolved in water, a positively charged sodium ion and a negatively charged chloride ion. The chloride is readily absorbed by the roots and transported to the leaves, accumulating to toxic levels and causing the tissue to turn brown.

The Amount of Salt Needed to Kill Barnyard Grass

• In a study published in March 1990 issue of "The Ohio Journal of Science," researchers found that solutions containing 2 percent sodium chloride killed all seedlings of barnyard grass, Echinochloa crusgalli. Most were killed with a 1.5 percent solution, though the percentage was greater in seedlings from a population native to a low-salt habitat and least in a high-salt habitat population.

Salt Tolerant Plants

• Some of the most salt tolerant plants are barley, sugar beets, sea buckthorn and silver buffaloberry. Triticale, rye and safflower are also highly tolerant. Among vegetables, asparagus and beets are the most salt-tolerant, with spinach and squash showing moderate tolerance. Roses show high tolerance and chrysanthemums, poinsettas and carnations are moderately tolerant. Among lawn grasses, bluegrasses are the least tolerant and tall fescue, bermudagrass and alkali grass are most tolerant. Most species show moderate levels of tolerance.