Root Cellars

My sweet potatoes are moldy.  Well, at least the random one I picked up the other day.  All the sweet potatoes are lying on newspaper, on the basement floor (except for the 3 that are on the stairs leading to the basement).  My basement is humid.  My city is humid, the other day it was 70 degrees and it's November.  I've had success with growing onions, shallots and garlic but some of them are lost during storage because the basement isn't dry and cool enough.  Onions are pulled in July and it doesn't get cooler until Oct.  What to do?

My mother suggested tubs with straw or sawdust.  Don't know where I can get straw this time of year or sawdust - mom lives near a paper mil in Maine, sawdust probably floats over her property for the taking.  I need to befriend a woodworker.

Mother Earth News had an article about how to build a simple root cellar.  Start with an old, cast off refrigerator and dig a hole large enough to sink the fridge in the ground to be flush with the soil - oh, I could see doing that here in DC!  Right next to the cistern I want to install to catch more water.

I have a garage where I could possibly build a little root cellar.  But I also have city animals and would be afraid that the produce would be pilfered.

Off to find a source for sawdust