The Underground Garden
Written onDecember 01 , 2007
Elliot Coleman, in his book Four-Season Harvest, says, “I think of my root cellar as a secret underground garden into which I spirit away many of my crops when winter threatens.” Many gardeners used to have root cellars; I am afraid it is becoming a lost art.
My good friend Robert King, who lives on Putney Mountain, built a root cellar in the 1970s on the hillside just south of his home. Easy access came from the gravel road, where he could drive his truck right up to the root cellar. The site was protected from the north wind and snow drifts. The door opened to the east, not the south where it would have received too much sun. Robert used the Scott Nearing simple stone construction method. First, pour concrete footings and then, using movable wooden frames, fill them with cement and rocks and let them dry. Then move the frames above the first-poured section and start again. It’s simple and practical.
Externally, the root cellar was seven feet wide and 13 feet long, which translated to five feet wide and 11 feet long inside. Robert built a framed, flat tar roof and used orange foam board to give the structure additional insulation, then filled in the sides with soil. Before you entered the root cellar, there was a mud room that provided an air-lock space between the outside and the cellar. This was why the structure was so long and why Robert could enter the root cellar with ease in the winter. Two half-doors swung in, then the main insulated door with two barrel bolts kept it shut. For ventilation, a four-inch aluminum pipe went through the top of the cellar. The pipe had a damper, just like those used with a wood stove. If it was too moist, the damper was opened all the way.
Timing is critical when using a root cellar because the temperature has to be cool enough to protect the vegetables. You don’t want carrots ripening in September when the cellar is still too warm. The key is to grow crops that ripen late in the season when the cellar has begun to cool down. The way to do this is to start opening up the doors in the evening and closing them in the morning. A rhythm of lowering the temperature starts in October and November. On a cold November day, a decision is made to harvest the root crops and fill up the root cellar, which now is the correct temperature.
The right root varieties are also critical. For example, Robert grew the ‘Lutz Winter Keeper’, a variety of beets, and Burpee’s ‘Short and Sweet’ hardy carrots. He couldn’t grow the longer, thicker winter keepers like my two favorites, ‘Nantes’ or ‘Danvers’ carrots, as his soil had too much clay. Carrots have difficulty penetrating heavy clay.
The root crops were stored in plastic milk crates found at the Putney dump. During the coldest times in winter, when there were seven days of sub-zero temperatures, a candle was lit in the mud room that kept the thermometer at 33 in the root cellar. If it had been colder, you know what would have happened.
In November, Robert made the last batches of apple cider. He would fill glass gallon containers to within 1/4 inch from the top and capped them. The sweet cider was unpasteurized. By then the temperature in the cellar was down around 35 degrees and the cider would keep all winter, believe it or not. Apples were not stored in the cellar because they gave off gases that affected the root crops, but they did store a five-gallon wooden apple barrel of vinegar.
Maybe we can all meet this winter in Robert’s Underground Kingdom. It would be a great place to see the many bins of potatoes, carrots, beets, turnips, and cabbage, and perhaps have a sip of sweet apple cider.
(This piece is excerpted from Ron Krupp’s “The Woodchuck’s Guide to Gardening”, a Vermont organic gardening book published in 2000.)