Tom said:One of the things that makes cypress and coco coir so good is that they resist any kind of mold or fungus even when sopping wet all the time. I have never attempted to bake or otherwise sterilize any of my substrates. I do rinse new cypress mulch before use though.
Alternatively, put the new sack in the freezer for a week if you have space!Madkins007 said:If you want a better chance at killing bad stuff, let it freeze for a few days in the winter, or sit in bright sunshine in a closed bag in the summer- the wet heat will take care of it.