Root Cellars, Cold Storage and Keeping food in the winter months!

I taught a workshop on root cellars in the fall and thought I would share some tips in my blog.  Storing your own food is awesome!  You can do it too!

For more information on root cellars and storage of foods:

• Root Cellaring  by Mike and Nancy Bubel.  PA. Rodale Press, 1979.
• Stocking up : the third edition of the classic preserving guide by Carol Hupping and the staff of the Rodale Food Center. 1986
• Mother Earth News
• There was good article in the Fall 2014 edition of The New Pioneer Magazine
• Ask your neighbour, your parents, your grandma... 

Kids veggie display Fall Fair, Salt Spring Island, BC

Why store food?

There are lots of reasons for which you might store food.

• Health
• Food security
• Supporting the local economy
• Save money
• Reduce your energy footprint
• Resiliency
• Eating with the seasons
• No time or energy to can/dry/freeze food

Keep your reasons in mind when designing cold storage because this might change your final design.

Bright Farm produce on the way to the Fall Fair,
Salt Spring Island

What food to store?

You can store many different kinds of food, but some foods lend themselves to be frozen, dried or canned better than being in cold storage.  Produce like potatoes, turnips, apples, pears, carrots etc keep really well.  Here are some tips on storing food:

• Store vegetables or fruit that you like to eat!  This may sound silly, but if you don't like turnips- don't store them just because they keep well.
• What can you grow or what do you have access to?
• Store a variety of vegetables and fruit. Variety is the spice of life.  Also- look for resources, or ask your neighbours, friends or local farmer if their are specific varieties of produce that store better than others.  For example, some apples and pears when picked in the late fall don't taste very good, but keep really well and ripen slowly in the root cellar making them great food to have in the early spring.
• Think about the 'hungry gap'.  The leanest time of the year is in the late winter/early spring when your root cellar supplies are dwindling but it's still not quite warm enough to be getting substantial food from your garden.  Store veggies and fruit that will keep until March/April, and think about using season extensions (row covers, greenhouses, winter gardening techniques) to get food out of your garden early in the season.

Apples from Bright Farm at the Fall Fair,
Salt Spring Island, BC

What are the storage requirements for fruits and vegetables?

This leads into two topics-  life after picking and how to design your built storage environment.

Life after Picking (Harvesting, Packing, Cleaning, and Curing)

Life After Picking

Your vegetables and fruit still breathe, even after they are picked.  This means that in order to maintain their living tissues, they consume oxygen and carbohydrates and produce carbon dioxide, water and heat in the process.   The more your produce respires, the more it deteriorates, and loses water, nutrients and flavour. Respiration rate is directly related to temperature (the higher the temperature, the faster a vegetable respires, or rots). This is something that is intensely studied because of the way that produce is picked and shipped all around the world to arrive at your supermarket.  Producers and transporters try to maintain the shelf life of the produce so that it arrives at your doorstep ready to eat.  This can also be applied to the conditions in a root cellar.  You want to keep your temperatures low, and maintain humidity in your root cellar so that your produce lasts longer.  Root vegetables don't ripen after you pick them, so you want to maintain their quality as you harvest and after you pick them.  

Leafy greens don't keep well, but are sometimes hardy enough to survive outside under row covers or greenhouses. Carrots, onions and beets keep well for winter storage.

Some fruit like apples, pears, plums, tomatoes release ethylene gas and ripen after they are picked.  For storage, ideally you would want to separate your apples/pears from your root vegetables, because the ethylene gas will induce rot in your other vegetables.  That being said, I have talked to many old timers who will store both kinds of produce together, and claim if you have good ventilation in your root cellar, it will not be as much of an issue.

Melons are delicious and ripen after picking but the best place to store them
is in your belly!

When/How to harvest?

Look up your frost dates and ask your neighbours when they harvest their produce.  A light frost (0C to -2C) is a sign of temperatures to come but isn't cold enough to harm root vegetables.  A hard frost (-2C and below) can be more trouble.  There is no exact temperature where your vegetables will be killed- it depends on the vegetable variety, the weather (if it is a prolonged cooling, or a quick cold snap) and the relative humidity. The longer you leave your produce for things like carrots and beets, the sweeter then will get and will reduce the water content in the vegetables.  This will make for better storage.  However, you don't want to wait too long for everything to freeze completely (potatoes especially don't do well with freezing).  For those who have milder winters, you can use mulch and cover your root vegetables and see if you can keep them in the ground most of the winter (although be careful of rot for those of you on wet rainy coasts).   When you decide the harvest, try to harvest your produce in dry weather. When harvesting, handle your produce with care.  Bruises can lead to rot!  

Mulched overwintered carrots- Photo by
 Stowel Lake Farm, Salt Spring Island

Curing/Cleaning/Selection/Packing

 Gently brush off dirt, but don't wash or scrub your produce before you store it in the root cellar.  Clip off any leafy tops (carrots, beets, turnips etc).  Cure onions, garlic, and squash in a warm dry place for at least a week.  It is also a good idea to select as you are packing your produce away.  Use up any forked, broken produce first (as they will not keep as long) and store good specimens. 

Sorting potatoes for the potato co-op, Linnaea Farm, Cortes Island, BC

You can pack or store your fruit/vegetables in crates, sawdust, leaves, sand, newspaper etc...  There are lots of different ways to store vegetables and fruits.  For more specific information ask your neighbours/farmer and take a look in Nancy and Mike Buble's book.  For anything, remember you need it to be accessible, keep rates of respiration down, you also need to be able to check periodically for spoilage.

Shelving and storage in a basement root cellar
 image taken from Bubel's book on Root Cellaring

The Built Storage Environment

Now that you know about how produce keeps, and how to harvest and store your produce, what kind of structure will you need? The largest considerations for a built storage environment is temperature, humidity and ventilation. I will give some key components of a built storage environment, as well as a few examples depending on your resources, goals, and level of permanence. Keep in  mind that although root cellars are the classic example that people use when storing vegetables, there are other ways such as: mounds/clamps, buried crops in rows, buried storage vessel (garbage can, old freezer, barrel), earth pit, insulated basement/shed.  I will put pictures/diagrams of all of these methods in the blog.

A Clamp/Mound is an easy, non-permanent storage solution. Once you open
A clamp, you need to use up all the veggies- so make many small clamps,
instead of one huge clamp.

Temperature

The largest group of storage vegetables and fruit need to be kept around 0C to 5C (carrots, beets, parsnips, apples, potatoes, pears, cabbage).  The rest are easier to find an attic, cold closet or another out of the way place in your house that is between 5C and 15C for things like squash and pumpkins. Get a thermometer to measure the temperature.  Even if you don't have a perfect storage environment, you can still keep produce for several months. 

Buried barrel to store produce.  Another easy, non-permanent solution
Diagram from Buble's Root Cellaring

Your storage environment should be able to get cold in the autumn, and then keep cold (but not freeze).  This is usually accomplished by siting the storage facility in a north facing hill, digging into the ground, insulating around areas that are not in the ground and having adequate ventilation. Digging a root cellar into the ground below the frost line helps to regulate the temperatures and moisture in the the root cellar.   The ground doesn't change temperature very quickly and as such it will be cool in early autumn, and also protects your root cellar from freezing in the winter months.  You also want to have a way to moderate temperature (manually or automatically) by opening a vent or a window.  It is also a good idea to insulate on any side of the root cellar that is not dug into the ground, or if it is in your basement, to insulate away from any hot water pipes and the rest of your house.

An hole dug into the garden, framed by a wooden box, covered by a piece of styrofoam to store root veggies. Erickson, BC

Humidity

Most root vegetables need 80 to 95% humidity to preserve the shelf life and turgidity of your produce.  Squash, onions and garlic need to be kept in dryer conditions (60 to 70% humidity) for best results.  Your root cellar will be more humid if you have a dirt floor instead of a concrete floor.  However, you can also raise humidity by sprinkling water on the floor, having a pan of water in the root cellar or adding damp burlap sacks over top of the produce.  

After the winter, the earthen pit is filled in and moved to a new location every
 year to avoid build up of pests and diseases

Ventilation

Ventilation affects temperature and humidity.  Remember that warm air rises and cool air falls.  You want to include and intake of air that goes to the bottom of your root cellar, and an outake of air near the ceiling of your root cellar.  For a root cellar 48sq ft you want at least a 4 inch diameter pipe.  Remember to screen it so pests can't get in!  

Sacks of root vegetables kept in the earthen pit from October to July
 Erickson, BC

Also don't forget there are other considerations to your design such as accessibility, drainage, shelving, size, resources you have, permanence, money. 

Large above the ground insulated shed for storing root vegetables at Canyon City Farm in Canyon, BC. The farm also has several other root cellar dug into the ground. The crates are filled with carrots that will be sold later in the year.  Sometimes above ground storage facilities need a light bulb, a space heater or some way to keep them from freezing when temperatures go below -20C.

How much to store?  How big of a root cellar?

A 50 to 100 sq ft root cellar is recommended- however it really depends on how big your family is, how much produce you might eat.  There are some estimations in bushels of how much a family of four might need to put away for the winter in Mike and Nancy's book.  The best way to know for your family is to take records of what you eat and how much.  This is an extrapolation from Nancy and Mike's book for two people (we have yet to test it):

• 40 lbs beets
• 75 lbs carrots
• 25 heads cabbage
• 55 lbs turnips/rutabaga
• 350 lbs potatoes
• 10 squash/pumpkins
• 50 lbs onions
• 40 lbs parsnips
• 10 lbs garlic



Family root cellar built into cool shady hill. Green pipe is the air intake.  (Exhaust vent for warm air is on top of the cellar, but not visible in this picture).

In the ground with row covers:

• 7 brussel sprout plants
• 20 leek plants
• 50 ft row of kale

Also keep in mind that you might have different tastes, you might preserve, dry, freeze or buy food in different ways.  Think back to your orginal intentions to why you want to store food in order size your cold storage environment.

Inside the family root cellar- with shelving that maximizes space and is away
from the walls to encourage airflow.

Other thoughts

• Watch your root cellar and check of spoilage
• Expect some produce to go bad- mistakes are tools for learning!
• Instead of building your own personal root cellar, maybe there can be a community root cellar?   What resources can be shared?
• Don't get too caught up on things being perfect.  We store food in imperfect conditions in our rental house (in a cold room and under our porch)- but it still extends our season of eating local produce and reduces our energy foot print.

Clapp's Favourite at the Fall Fair, Salt Spring Island BC