What will happen if I get some fig and grapes cuttings, buy a bag of Miracle Grow potting soil (moistened), open the bag at the top, insert the cuttings all the way to the tip of the cuttings and store the bag at 8C~10C (say 46F~50F) until the end of March while I am away from home. Our fridge has frozen the cuttings in the past.
Is there probability of rot, mold or other negative aspects?
Also, should I expect some rooting action or initial formation at these temperatures?

Ottawan,
In your climate you must keep house door closed so things do not freeze in fridge.  ; ).
All kidding aside im not sure about the method you speak of  (never tried) but i do keep my sour dought culture inside the door of fridge which is warmest part of it with no problem in glass mason jar.
A Happy Thanksgiving to You and Family
Martin

Ottawan,

Not sure what would happen either. If you have the ability to store these at the temperature you mentioned (46-50 F), then why would you not consider storing in a more "traditional" way? I would think that if you prepare the cuttings and clean with diluted bleach solution, then wrap in damp newspaper and put in ziplocks, you might have a good chance to keep them until March. The temperature is warmer then you would want (a refrigerator should be at about 38) and holding them until March is a little long if you can not periodically check for mold. The alternative method you mention might also work and could even result in roots developing and growing during storage. It is an interesting question you ask and I am sure others will have some recommendations. Best of luck.