Potato Storage

by Peter Heffelfinger

posted September 28, 2020

 

I often think of potatoes as pioneer food, since the tubers would last for months while being transported long distances and then could be planted in the first available spot at a new homestead. No special soil or cultivation needed, at least for the initial crop, and no extra fertilizer required the first year since the potato itself was a self-contained nutrient supply for the young seedling. I imagine the early settlers in the Pacific Northwest sticking a few precious potatoes in the open ground between the newly fallen old-growth trees. Potatoes were the easily grown carbohydrate that was not only a complete food nutritionally, but could be also be stored easily all winter. No wonder potatoes, first domesticated in the New World, rapidly spread to the other continents.

These days, before digging up the potatoes, I let the vines completely die down and then sit undisturbed for two weeks in order for the soft potato skins to harden up. In past years I washed down the freshly dug tubers with a hose and then let them air dry in the sun for no more than half a day, being careful to avoid any green skin spots developing from over-exposure to light. [Note: the green skin layer on a potato should be removed and not eaten, since it develops a harmful substance.] My thought was that washing would help prevent any soil-borne diseases from being carried into the storage containers. It has worked fine to date, but it was a full day of work to prepare the spuds for storage.

Recently a Master Gardener column stated that it was safe to store potatoes unwashed, I assume to limit any exposure to water or to avoid the spread of disease. So, this year I merely rubbed any dry soil off, and got rid of any rotten or obviously diseased tubers. I always have a few with brown rot in a hollowed-out core, but it hasn’t been a major blight for me to date. (I have heard this year, however, from another local gardener with that disease in his red potatoes.) A small amount of scab on the surface seems to be ok since it doesn’t penetrate the skin enough to cause spoilage later on. Any potatoes damaged from digging I put aside for immediate use since freshly broken skin areas would soon decay.

All in all, potatoes are susceptible to a variety of diseases, but it is possible to have a good crop as long as you practice good garden hygiene, rotate your growing site, and make sure to plant in our native acid soil (no lime application the winter before or just prior to planting). And use certified, disease-free seed potatoes. I rely on varieties that do well locally, such as Yukon Gold, California Whites, a standard Russet, and whichever Red is available each year. I’ve found that East Coast varieties such as Kennebec don’t seem to do well out here, perhaps due to different soil and milder weather. I’ve grown the purple potatoes originally from Peru, which did very well, but they’re a visual challenge on the plate.

For storage containers I use cardboard boxes filled just halfway with potatoes, with a layer of newspaper inserted against the side-walls to block the light from any handle or ventilation openings. I also add several layers of newsprint on top of the potatoes before folding over the top flaps of the box. The aim is to seal out any possible exposure to light. I find that the half-filled box allows the tubers to breathe a bit, since they give off a lot of moisture in storage. The newspaper acts as a sponge to soak up any extra humidity that might cause rot.

Fresh-dug potatoes are essentially seed plants over-wintering in the dark, waiting for spring. Actually, they don’t wait very long before the ‘eyes’ start sprouting, usually by mid-winter. I check the boxes regularly, rubbing off any new sprouts as they appear. If left to grow out, the sprouts will turn into active roots, and the entire box will soon turn into a nest of interlaced white roots. The potatoes themselves will have started to turn soft, since they are feeding the roots. If carefully de-sprouted at least once a month, I find that boxed potatoes will last most of the winter.

Note: To avoid confusion later on, limit each box to one variety and label it on the outside. Varieties of potatoes may have shorter or longer storage lives, not to mention differing densities that will affect cooking times.

I keep the boxes on a cool concrete floor of an unheated laundry room, next to a freezer and a storage fridge for fermented kraut and pickles.

The appliance motors supply just enough indoor warmth to protect any stored produce from freezing, but not too much heat to cause spoilage.

If any of the potatoes do eventually become too sprouted and soft, process them en masse by removing the sprouts, paring off the softened skins and boiling them all up. I let them cool and then store in freezer bags as a last supply of potatoes for the tail end of winter. Not the highest quality fresh produce, but they are homegrown, organic, and good for soup or hash browns. Plus, I always feel committed to using up what I have raised myself. Any potatoes that are too far gone, however, end up in the worm bins.

In order to avoid disease, I don’t use any homegrown potatoes as seed the following year. I always buy fresh seed potatoes each spring, since they’re checked to be disease-free, having been grown in drier areas that are less prone to the many diseases that potatoes are prone to. Of course, if you’re attempting to maintain an heirloom variety, you’ll have to use the healthy-looking potatoes left in storage, sprouts and all. That is what the pioneers did, and certainly what the Incas still do in the Andes, where potatoes were first domesticated.

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