Any advice on potato/root storage cellar?

This could be a topic of very narrow interest but does anyone have advice on creating a successful root cellar that maintains 32-40 degrees for most or all of the year? We built an extension on to my house and I added an above-ground pantry/storage area that has no heating on purpose but is still connected to the house. Beneath that I have a 20×20 area accessible by trapdoor and separated from the rest of the crawlspace with insulation but is maintaining a consistent 58* and 85% humidity in our Alaskan summer. My house is very tight and energy efficient and I’m worried this will work against my efforts to achieve a proper under-house root cellar. The temp in my main crawlspace/subfloor is usually about the same at the room temp above due to effective insulation and radiant heat from above. I blocked off this 20×20 area from the rest of the subfloor to attempt to make it cooler but with limited effect thus far. Also very concerned about high humidity inducing mold. I’m considering venting this cellar thru the pantry above and then into the outside with pvc pipe (one in and one out) and inline fans that could draw in cold air during the winter or be completely closed to avoid freezing. Temperature control via small fans that would also release the moisture. I’m sure this will get cooler in the winter but I’m worried the radiant heat from the house will keep it above my ideal storage temp even in the winter. Anyone deal with something similar or have thoughts on this? Much appreciated!


  • Comments (6)

    • 2

      Your strategy of pipping in outside air and venting is the same thought that I had with the ability to close it off during the colder months. Now only if you could program the vent to self-operate according to the internal temperature and humidity.

      • 2

        Venting can definitely be managed. We use one of these to cool the “cellar” in winter, and one to turn a heat lamp on in the cold frame.  The one in the cellar operates a blower that was saved from a Jenn-Aire downdraft stove.  You just change the wiring for heating or cooling.  Humidity needs some hands on intervention.  We raise the humidity in the cellar (when storing potatoes, etc.) by sloshing water on the gravel floor, or with buckets full of water.  But now that it is in use for preserved foods, a dehumidifier both warms and dehumidifies the space.  thermostat

      • 1

        I’m considering asking an HVAC contractor to quote me on basic vent system with fans and temp control. I probably won’t take them up on the quote but I’ll gain some insight into how a pro would put this together. Thanks for the comment!

    • 4

      This book will answer all your questions.  Root Cellaring  We used principles in this book to create a partially underground space.  We are in western Oregon, not nearly cold enough for a “real” root cellar, so the space has been committed to other types of food storage.  That being said, it is maintaining a steady 68 degrees through temps in the high 90s-100s.  In winter it will go down to about 45, with a fan and exhaust vents.  If it was fully buried, I think it would probably maintain a temperature in the 50s.

      • 2

        Thank you for the reference book and insight Barb. I ordered a copy and will check it out. I’ll update this winter with results!🤞

      • 2

        I really look forward to reading your updates!  Even with only modest success in cooling our “cellar”, using storage techniques recommended in the book got root veggies through the better part of the winter.  The trade off of not really being able to store a winter’s supply of fresh food is our ability to do “sheltered gardening” through the winter.  Our climate is usually favorable to growing a winter garden, with protection from rain and occasional dips in the temperature.  I’m frantically populating the “hoop house” with winter veggies at this time.

        We are able to very successfully store some veggies in insulated, unheated outbuildings.  Well cured onions and winter squash keep really well, in drier, somewhat warmer storage.  Potatoes actually last quite a long time in a corner of a shop building.  There’s so much great stuff in that book, including recommended “keeping” varieties.

        Barb Lee (Formerly posted as Dogpatch)