I have lost a few nice plants this year that are susceptible to root rot in cold and wet conditions. Typically I have brought on the root rot after trying to transplant the plants from a container with gritty mix into a new container with gritty mix. Sometimes I put gas on the fire by watering the plant shortly after the transplant. The combination of the transplant, watering, and cold conditions just take the plant quickly. I have lost an Adenium and an Encephalartos this year, among others.

Does it make any sense to try to sterilize gritty mix in the new container before attempting to transplant such sensitive plants in the Winter? I am thinking in terms of watering the new container with boiling water or maybe pre-treating with an antifungal. What is a recommended procedure for sterilizing the gritty mix in the new container?