I have a rose cutting in water and it has developed 6-8 roots that are about 3 inches or more in length. I am unsure what the best soil is to transition this cutting to and the best way to do it. Also how moist do I need to keep the soil after the transition to soil?

I want to minimize the possibility of losing this rose, as it was a rose from an arrangement from the death of my infant grand daughter on August 30th of this year. Any assistance or advise you can give me would be awesome. The rose is in a window facing the south.