Gypsum is a soft white-grey mineral known as a ‘clay breaker’ because it helps to improve the physical condition of heavy clay soils. In layman’s terms, if you look at compacted soils under a microscope they look like a jar full of sand. If you mix gypsum with the soils it will then look like a jar full of marbles, with air pockets around them. The result of this occurring is to allow better water and root penetration. Root development and the intake of other essential nutrients are assisted as well by the calcium content of gypsum.
As a rule, gypsum is best cultivated and mixed into clay or heavy soils prior to laying turf or adding turf underlay. If you have an existing lawn that is suffering from compaction, using gypsum will also help relieve compaction in most clay or heavy soils. First aerate the lawn, then spread 1-2kg/m2 of gypsum over the lawn and rake in. If you’re unable to aerate the lawn first, water the gypsum in heavily once spread. Remember good soil structure will give you a great lawn. If you want more advice, get in touch with your local Lawn Solutions Australia member.