Iron sets back mosses while having little effect on the grass. However, iron will not always kill the moss. It may “burn” the moss severely and render the plant very weak. If the moss is to be eliminated, it must be removed and grass seed sown into its place for a thick turf.Click to see full answer. People also ask, how long does it take for sulphate of iron to kill moss?Always try to apply Sulphate of Iron on a dry still day but with rain imminent – ideally no longer than 12 hours . (this is to avoid scorching) the moisture dissolves the sulphate of iron. Once the moss has died back, you can scarify out the debris – ideally 5-14 days after application.Also, does liquid iron kill moss? High concentrations of iron are toxic to moss and weeds, and can kill them without the use of toxic chemicals. Mix the liquid iron at 2 oz per quart of water, 8 oz per gallon. Using a pump or trigger sprayer, wet the moss well with the iron solution, being careful to avoid spraying the grass. how does iron sulphate kill moss? Moss Killer / Control – Sulphate of Iron 20% Fe is very effective at controlling moss on your lawn. To use, apply 5-10g of solid crystals direct to each 1m2 of Lawn. Only apply solid product when its raining or about to rain; if not dissolve 5-10g in 1 litre of water and apply.How do you rid your lawn of moss? Ways to Kill Moss on Your Lawn For small patches, mix in a garden hand sprayer 2 ounces of dish soap and 1 gallon of water. Spray the mixture on the patches of moss. The patches of moss will turn orange or brown in 24 hours and eventually dry up. After raking up the dead moss, take it to an isolated area.