Storing potatoes

With more than a tonne of potatoes as our reward for a year’s hard work, it’s worth taking the time to store them properly as, with care, they should last at least nine months.

We store our potatoes in two large, galvanised steel coal bunkers, each with a capacity of 500kg.

But it’s much more complicated than simply emptying buckets or sacks of potatoes in the bunkers, shutting the lids and hoping they’ll last.

Having lifted the potatoes, dried them in the sun for a few hours or undercover in bad weather, and then packed them in hessian or paper sacks, the next job is to store them somewhere cool and dark for about a fortnight.

This gives moulds, funguses and rot time to develop to the stage where they’re easily spotted, but without spoiling all the potatoes.

We then gently empty each sack of potatoes before inspecting and sorting them.

All the potatoes that show signs of rot are thrown away, as are most of those with mould and fungus.

We put aside any potatoes with just a few strands of fungus growing out of cuts, holes and scrapes as these areas can be cut off and the remaining potato used for pig feed. However, these are used within a few days.

After that, it’s time for sorting the potatoes.

First, make sure different varieties are separate from each other.

Salad potatoes, first earlies and second earlies do not keep well and should be used within a month or two of lifting. Mature maincrop potatoes are the ones to store.

Starting with the salad potatoes, first earlies and second earlies, divide the potatoes into three piles. Those that are too small or fiddly to cook; those that are cooking sized by blemished or damaged; and those that are cooking sized and unblemished.

The small discards can be used for animal feed, chopped up and composted in the centre of a hot compost heap, or disposed of (a fire is best).

The blemished and damaged potatoes should be used first, while the best examples should be used last. Both lots should be stored in paper or hessian sacks in a cool, dry and dark place.

Sorting maincrop potatoes is slightly more involved.

First, remove all the larger, unblemished potatoes. These are the ones with a diameter of at least two inches that will be kept for long-term storage. Put these to one side.

The remaining potatoes should be sorted and stored as for the first and second earliers - the small discards, the ones for immediate use and the ones for medium-term use.

With them out of the way, it’s time to turn your attention to the long-term storage.

You can clamp maincrop potatoes outside, but heavy frost will penetrate an earth and straw clamp so we don’t use a clamp and I won’t go into details here.

Our particular solution is a combination of clamping and indoors cool storage.

We use metal storage bins as they’re rat-proof and coal bunkers because they’re much cheaper than similar sized metal feedbins.

The bottom seams are reinforced with pop rivets and the bins placed along the centre line of the hay shed, keeping them as far from the walls and the cold outside temperatures as possible.

We then place a layer of straw in the bottom of the bin and then place potatoes in rows on the straw. This should be done carefully and gently to avoid bruising the potatoes or having them touch each other (if they touch, then it’s much easier for rot and fungus to spread).

Once a layer of potatoes has been completed, another layer of straw is added and then another of potatoes until the bin is almost full. A final, extra thick layer of straw is then added and the lid closed.

To help keep the potatoes dry, good airflow is essential so air must be free to enter the bottom of the bin and exit the top. This is easily done by drilling 1cm wide holes around the based of the bin and either chocking the lid slightly ajar or drilling a circle of holes in the centre of the lid.

Check the bins at least once a week, and here good sense of smell is very useful as rot has a pungent aroma. (The potatoes should smell of cold, dry earth.)
As our hay shed gets quite warm from late May onwards, that’s also the limit for storing our potatoes in the bins. At some point I’d like to get some styrofoam insulation sheets and line the bins with them as this will protect the potatoes from both cold and heat, but that has to wait until we can manage to scrounge some and the bins are empty.

To aid ventilation it would be worth putting a couple of 12v computer fans on the lids as extractors, and power them from a small wind turbine or solar panel. By drawing air up through the straw, this should keep the potatoes quite dry and with minimal cost.

But for now, we’ll aim to store our potatoes for eight months and then see how things go.