Storing Root Vegetables Over Winter: The Damp Store, Dry Store Rule

A garden that feeds you in July is lovely. A garden that is still feeding you in February is the real prize, and it comes down almost entirely to how well you store what you grew. The good news is that most of it needs no freezer, no special kit and no electricity at all, just a cool corner, the right conditions, and a little care at lifting time. Homesteaders have kept themselves in vegetables through the hungry gap for centuries with nothing more than sand, straw and a cold shed.

Before the crop-by-crop detail, there is one idea that unlocks all of it, and it is worth getting straight in your head first. If freezing is more your thing for softer produce, that lives in its own guide, freezing the harvest; this page is about the slow, cold, no-power kind of storage.

The one rule that matters most: damp store or dry store

Storing produce is really about slowing it down. A carrot or an onion is still alive after you lift it, quietly breathing and gradually using itself up. Your job is to keep it cool enough to almost stop, frost free so its cells do not burst, and at a humidity that neither dries it out nor lets it rot. Get too warm and it sprouts. Freeze it and it turns to mush when it thaws.

Where crops differ is what humidity they want, and this is the split that decides everything else.

Damp storage	Dry storage
Carrots, beetroot, parsnip, turnip, swede and celeriac	Onions, garlic, shallots, winter squash and pumpkins
Cool and just above freezing, humid at around 90 to 95 percent	Cool, dry and airy (squash wants it distinctly warmer)
Left in the ground under mulch, or boxed in damp sand	Cured to dry the skins first, then hung or racked in a single layer
Too dry and they shrivel; too wet and they rot	Any damp at all and they go mouldy and rot

Roots are mostly water and shrivel if the air is too dry, so they like it humid. Onions and squash carry disease the moment they get damp, so they want it dry. Put a crop in the wrong camp, a bag of onions in moist sand, say, and you will be composting them by Christmas. Keep that distinction in mind and the rest is detail.

Maincrop potatoes

Potatoes for winter storage are a slightly different job from new potatoes, which you simply dig and eat. For keeping, you want the skins to toughen up first so they survive the months ahead.

Lifting and storing maincrop potatoes

1. 1

   Wait for the foliage to die back

   Once the top growth yellows and flops, cut it off at ground level. This tells the tubers the season is over and starts the skins setting.

2. 2

   Leave them 10 days

   Give the tubers about ten days in the ground after cutting the tops, so the skins toughen and store better.

3. 3

   Dig on a dry day

   Lift gently with a fork on a dry day, and let the potatoes sit on the surface for a few hours to dry off.

4. 4

   Sort and brush, do not wash

   Brush off loose soil but never wash them, and set aside any that are cut, bruised or diseased to eat first, not to store.

5. 5

   Store in the dark in breathable sacks

   Put only sound, dry tubers into paper or hessian sacks or slatted trays, somewhere cool, dry and frost free like a garage. Check every couple of weeks and use them before they sprout in spring.

The single non-negotiable with potatoes is darkness, and it matters for your health, not just for keeping.

Carrots, beetroot, parsnip, turnip, swede and celeriac

These are your classic damp-store roots, and you have two routes. The first is to leave them in the ground. On free draining soil this works beautifully: simply cover the row with a thick mulch to keep the frost off and lift the roots as you want them. The RHS suggests around 15 centimetres of straw or bracken over carrots, swede and turnips, and a more generous 30 centimetres over beetroot, which is a little more tender. Left like this, many roots keep happily until about March. The catch is wet ground. On heavy, waterlogged soil they will simply rot, so there you are better lifting and boxing them.

Parsnips deserve a special mention here, because a frost genuinely improves them. Cold weather converts some of their starch to sugar and makes them sweeter, so leave parsnips in the ground and dig them through winter and into early spring rather than lifting them early.

The second route, and the one for wet gardens or for clearing a bed, is boxing in damp sand. It recreates that cool, humid, dark environment in a box you can tuck in a shed or cellar.

Boxing roots in damp sand

1. 1

   Lift and sort

   Lift on a dry day and set aside anything bruised, forked or damaged to use straight away. Only perfect roots go into store.

2. 2

   Remove tops, keep the soil

   Twist or cut off the leafy tops and shake off loose soil, but do not wash the roots, as wet skins invite rot.

3. 3

   A bed of damp sand

   Put a layer of damp, not wet, sand in the base of a box. It should feel like a wrung-out sponge, not soggy.

4. 4

   Layer so they never touch

   Lay the roots on the sand so they are not touching one another, then cover with more sand and repeat in alternate layers, finishing with a good capping of sand.

5. 5

   Cool, dark and frost free

   Store the box in a cool, dark, frost free shed or cellar and check every week or two.

Onions, garlic and shallots

Here we cross into the dry camp, and the make-or-break step is curing. Onions, garlic and shallots need their skins and necks fully dried before they will keep, and storing them even slightly soft is the fast route to mould.

After lifting, spread the bulbs out to dry for about two weeks with air reaching all around them, ideally on a wire rack in the sun, or under cover in a ventilated shed if the weather turns wet. They are ready when the necks are papery and the outer skins rustle. Only then move them into store: net bags or shallow trays in a single layer, or the traditional plait or string hung up out of the way. Shallots you can split into individual bulbs and trim the leaves. Garlic follows the same simple principle, cure it well, then keep it cool, dry and airy.

Keep well-cured onions and they will often last eight to ten months, with shallots keeping longer still, sometimes up to a year and a half. Look them over occasionally and pull out any that feel soft at the neck, because as the old saying goes, one rotten onion will spoil the string.

Winter squash and pumpkins

Squash and pumpkins are dry-store crops too, but unlike everything else here they want warmth, not cold, and that changes where you keep them. First, only store ripe fruit: the skin should be hard, the colour even, it should sound hollow when tapped, and any surface shine should rub off. If your thumbnail digs into the skin it is underripe, so eat those first.

Leave a little stalk on each side of the fruit and avoid bruising them. Then cure them: ideally around 26 to 29 degrees for 10 to 14 days somewhere sunny, turning them halfway, which hardens the skin and sweetens the flesh. Those temperatures are demanding for a British autumn, so treat them as the ideal rather than a rule.

Apples and other tree fruit

Apples store well but to their own rules, so the short version is this: keep only perfect, unblemished fruit, wrapped or spaced so they are not touching, somewhere cool and frost free. For the full method, including which varieties keep and how to wrap them, see our dedicated guide on how to store apples.

The traditional clamp

If you are storing roots by the sackful, the old-fashioned clamp does the same job as a box of sand but on a bigger scale, outdoors. Choose a sheltered, well drained spot and lay down about 20 centimetres of sand or soil topped with straw. Stack the roots in a pyramid, biggest at the bottom, then cover the heap with roughly 20 centimetres of straw and 15 centimetres of soil patted smooth, leaving a small twist of straw poking out of the top as a chimney to let warmth and moisture escape. Built about a metre high, a clamp keeps a large harvest through winter. The main enemy is rodents, so keep an eye out for burrowing.

The rules that apply to everything

Whatever you are storing, a few universal habits make the difference between a full larder in March and a bin of rot in January.

• Store only sound, unwashed, dry produce. Washing or nicking the skin opens the door to rot. Set damaged items aside to eat first, and never put them into store.
• Do the "one bad apple" check. Look over your stored crops every week or two and remove anything that has started to rot the moment you spot it, before it spreads to its neighbours.
• Label your boxes and sacks with what and when, so you use things up in the right order.
• Keep rodents out. Mice and rats love a shed full of stored veg, so control them, keep sacks off the floor, and check clamps for signs of digging.

Before you store anything: a quick checklist

1. Is this crop a damp-store root or a dry-store bulb or squash? Put it in the right camp.
2. Is every item you are storing sound, dry and unwashed, with the damaged ones set aside to eat now?
3. Have you cured onions, garlic, shallots and squash properly before they went into store?
4. Is your store cool and frost free, dark for potatoes and roots, light and airy for onions, warmer and indoors for squash?
5. Have you put a reminder to check everything over every week or two?

Storing your own harvest is one of the most satisfying parts of growing it, and it is forgiving once you have the damp-versus-dry rule in your bones. Start with a box of carrots in sand and a string of onions this year, see how they keep, and build from there.