Root Cellars – keeping it cool without refrigerators
Root cellars have been around in one form or another forever and for good reason - they work! If you have a below ground basement in your home, you pretty much have the makings of a good root cellar.
You may recall from our article on the Ground Heat Exchanger, if you dig down thirty feet or more, the ground temperature stabilizes at roughly the same temperature as ground water – depicted on the figure below (from http://www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm
As with most things, root cellars run the gamut from simple to complex and cheap to expensive. When you dig down even a few feet, the temperature drops considerably. Thankfully the humble root cellar lends itself to simple AND cheap and in this article we will be describing how to make the simplest and cheapest root cellar of all - the Trash Can root cellar.
Fun Fact: The Statement of Work for a 2012 US military-funded aid program for a country in Central Asia included a requirement to install a root cellar at each of 9 locations. It was determined by the recipient country that given the unreliability, electrical service and other logistical constraints, a root cellar was a more secure way to preserve food for their troops than modern refrigerators.
Site selection is important. Things to consider are:
► Location: Proximity to the kitchen for convenience.
► Drainage: A well-drained site which will not have run off going into it.
► Shade: A shaded area to prevent the sun from overheating your stores. In the northern hemisphere, the preferred location would be the northern side of the house (the side where the last bit of snow remains before the spring melt). This can also be accomplished with a make shift roof to provide shade.
► Soil composition: Don’t dig too close to large trees which may have roots that could make digging difficult. Very rocky soil is also hard to dig in. Be mindful of the water table, especially if it fluctuates. Anything stored below the water table is destined for rotting.
Once a suitable site has been determined find a suitable person to dig the hole. In my family that would be my son. I call it character building, he calls it child slave labor. I think he is being overly dramatic…
The hole should be deep enough so that when you place the trash can in the hole about 4 inches of the can extends above grade. You can also dig the hole deeper and place the trash can on a cinderblock. In this case, you may punch some holes in the bottom of the trash can so any moisture will drain out. You can pack snow or ice beneath the trash can to provide cooling for when the weather warms up. 12 inches of well-packed snow with a 4-inch layer of straw on top of it can last all summer in the Midwest. Make the holes 2 inches wider than the diameter of the can to allow for air circulation.
A note about the straw- do NOT use green material at this could easily compost, even in the late Fall. Composting materials generate heat, which is bad in this instance. Be sure your straw is dry.
Pile about 12 inches of straw on top of the trash cans (be sure to put the lid on the can) for insulation. Finally, you want to keep it all dry so cover the straw with a waterproof tarp and weigh it down.
The best place for root crops is (surprise) in the ground! If you are growing your own root crops, don’t harvest them until you plan to eat them or until you have to. This usually coincides with the freezing of the ground to the point where it can no longer be worked. When you do harvest them, remove the greens and gently brush off as much dirt as you can. Don’t wash them as this can damage the skin and make them more prone to spoiling. When you are brushing off the dirt, be on the lookout for bruised or soft spots as well which may harbor mold spores that can damage everything you have stored. Donny Osmond may have said “one bad apple don’t spoil the whole bunch girl” but he was NOT stocking a root cellar. Other foods such as apples or the brassica family also lend themselves to storage in root cellars.
When you place your produce in the trash can, use straw or some burlap to separate layers and permit air to circulate and absorb excess moisture. Your produce doesn’t need to be clean in the root cellar – you can wash it when you take it out to eat it.
The Trash Can root cellar is a very good introductory project to get to understand the practical science of food storage. Eventually you may want to design a larger root cellar as part of a basement or as an adjacent room to your house. More elaborate root cellars will have lighting, ventilation fans, integrated shelves and can even serve as storm shelters as the one we had growing up.
Remember that the Statement of Work for an American military-funded aid project to a Central Asian country in 2012 had a requirement for root cellars at each site. Total cost for you might be a couple hours of work and $35 for materials including the trash can. Total cost in that US funded project, hmmm – probably a lot more. Your tax dollars at work!
The only easy day was yesterday – keep on prepping .