Home Improvement Questions? Ask a Handyman for Answers
Hello again, I cannot see the house lay out from here, but it sounds like the root cellars are adjacent to the basement with the cold air return in it.... and that is what allows you keep the basement warm in the winter.Changing all that around could be both difficult and costly. You may have to simply fit air tight doors between the root cellars and the basement...and if that fails, make the walls and floors of the root cellars out of concrete so that the odors the microbes generate to not get into the root cellar.Microbes breath and pass gas just like other animals... that is what you are smelling. Cement floors and walls will solve 98% of that.
I will be off duty until 5 pm San Francisco time, then back from 5 pm until 11 pm if you need more explanation.