Moss can be a nuisance in your lawn, but it’s not impossible to eliminate. With the right treatment, you can get rid of moss and have a lush, healthy lawn. One of the most effective ways to kill moss is to use iron sulphate. According to gardening experts at Moowy, iron sulphate can kill moss in as little as four days. It also helps your grass produce sugars through photosynthesis, which enhances plant strength and gives your lawn a deep green color.