Gypsum is supposed to help with high salinity in your lawn. Is this true and where do I buy it?

Answer 1

Gypsum has very little effect on the acidity or alkalinity of the soil. The way it does help to get salt out of the soil is that it loosens the electrostatic charge between soil particles, thus loosening the soil. When the soil is looser the water leaches through easier taking the salt with it out of the root zones of most plants.

You can get pelletized gypsum at nearly any good lawn and garden center but call first. Sometimes they may not have it at this time of year. Put it down according to the instructions. A 40# bag will do about 1000 sq ft.

Answer 2

No, gypsum does nothing with the salinity in the soil. It can have some effect on the alkalinity (basicity) of the soil, but that depends on the pH of the soil, as far as how much it will change the pH.

Gypsum is a neutral salt, NOT a liming material; it can lower soil pH IF there is available Aluminum (Al3+) in the soil. (Ca from gypsum displaces Al from exchange sites in the soil, then the AL hydrolyzes in the soil solution, releasing hydrogrn ions; otherwise it has NO effect on pH.

Gypsum contains sulfate, but this does not lower soil pH, elemental sulfur, not sulfate, lowers soil pH.

You can buy a liming material at any home improvement store, but if you have a problem with salinity, you probably need to check the salinity levels of your water and plant salt tolerant plants.