What specifically are you attempting to root?
I find that many plants, shrubs, and trees will root without using anything more than soil... although, many do have a specific season where they are more receptive to being stuck.
One more natural method that I've heard of.... Is using a grain like wheat... No reason why rice or something similar wouldn't also work... The sprouting grain releases hormones that encourage root development on the plant that you are attempting to propagate.
