Nothing, the biochar will activate after the first natural rainfall. If no rainfall is expected we would advise watering heavily to speed up the activation. If you are planning on turfing our recommendation is to leave the soil as is, after treatment, do not break the surface or rotivate. Add a small amount of top soil and turf. If grass seeding, lightly rake the surface and add seed. If no grass or plants are added the treatment could start to decline as the rain will wash away the stop surface and fill in the cracks and voids.