Long Term Storage of ‘Fresh’ Fruits and Vegetables

In many countries fruits and vegetables which are able to be stored long term were put in root cellars.  These were sometimes located under the house and may have incorporated the cool larder, but in their most basic form they were dug out pits with an earth bermed roof away from the house or the more basic ‘clamp’ (roots crops stored on the ground with straw or bracken and covered with soil). Root cellars utilised the natural cooling, insulation and humidity of the earth to keep crops from freezing over winter and reduce spoilage in summer.  As most areas of New Zealand are able to grow root crops and hold them in the ground all through winter, root cellars are not really used here. However, earth bermed pits were used by Māori for storing kumara (rua kūmara) as they will rot if left in the wet cold ground.  

Usually these fruit and vegetables (below) are only being stored over the cooler months, which means they can be stored in a suitable shed or under the house, in an unheated room, even on a veranda or back porch as long as humidity can be loosely managed and they are (mostly) kept in the dark. Air flow is important in most cases to prevent a build-up of moisture which can cause rotting and to reduce build ups of ethylene gas (a natural ripening gas emitted by apples and other fruits and vegetables like onions and garlic etc) The use of untreated wood for shelving and boxes or bins has the added benefits of natural antimicrobial and antibacterial properties. Having a dirt or gravel floor in your outdoor storage spaces helps to regulate humidity levels and can provide good drainage. If your main storage space is outside of the house consider using a cool cupboard inside and restock it occasionally from the outside stores. This means when the weather gets stormy or you are busy there is a food store close at hand. 

Conditions for storing depend on the produce but they are mostly divided into those which need high humidity (as in root cellars or cool sheds) and those which need low humidity (like in a pantry). Choose only undamaged fruit or vegetables for long term storage. 

High Humidity crops 

Apples 

For maximum apple storage life, make sure that you harvest the apples when they are mature, but not fully ripe. That is because apples will continue to ripen while in storage, so ripe or overripe apples will quickly become soft and floury.  As they ripen apples give of ethylene gas, this gas speeds up the ripening process of apples and any other fruit or vege around them so ventilation is important. Apples store well at low temperatures, 4°C is a pretty good temp for most apples. Above this and they will ripen faster, below and some varieties can suffer chill damage.  Humidity should be at 90 to 95% but as this can be hard to maintain wrapping the apples in newspaper can help retain moisture. Then layer the apples in crates, boxes or even drawers, preferably in a way in which you can easily check for rot, cardboard between the layers can help with this. Apples stored this way can last 2 to 7 months depending on the variety, tart crisp apples generally store longer. 

Pears 

Pears can be stored much the same as apples, the European pears such as ‘Bartlet’ ‘Packham’ ‘Beurre Bosc’ and ‘Winter Nelis’ should be picked firm and slightly under ripe. Stored like apples they should last 1 to 3 months. Remove from cold storage about a week before eating so they can finish ripening. 

Asian pears or Nashi however should be left on the tree until their colour changes and they are sweet, crunchy and juicy. Store as above for 1 to 3 months. 

Most other fruits (stone fruit, berries etc) have short fresh storage periods and are best bottled, dried or frozen to preserve the harvest. 

Potatoes 

Late crop Potatoes are the ones which you store for use through winter and are dug once the plants die back.  There are a few ideas on what to do with potatoes once dug, some say leave them in the sun for about a day and a half to allow the skins to cure. Others say to cure in a dark place for 10 to 14 days at about 7 to 15°C. Once cured potatoes can be stored in a cool dark airy place for 4 to 6 months or more depending on the variety. Keep the potatoes separate from apples and other fruit or veges, like onions and garlic, which produce ethylene, a ripening gas, as it can cause the potatoes to sprout early.  If storing in sacks, hessian or paper is best as it allows the potatoes to ‘breathe’, otherwise crates or boxes can be used, and layers of paper, sacking, straw or bracken etc can be used to cover to keep out the light. The bracken or straw is also thought to absorb some of the ethylene gas and therefore prolong storage time. Sprinkling lime on each layer of potatoes is thought to prevent mold and rotting and also stop the potatoes from sprouting. 

Carrots, beets and parsnips 

It most places these root vegetables will store well in the ground and you can spread a thick layer of straw over the top of them if you are in an area with very low temperatures where the ground freezes. If you would rather store inside, or need the space in the garden these crops can be layered in damp sand, saw dust, peat or moss. For carrots and parsnips remove all the green leaves and stems, for beets cut back the stems to about 2 to 5 cm, try and keep the beets roots intact. Make sure they are not touching each other in the layers. 

Carrots should last 4 to 6 months, beets 3 to 5 months and parsnips 1 to 2 months. 

Turnips, radish (black spanish, daikon etc) and swedes can be stored the same way but it is often recommended they are stored outside due to their strong smell. 

We choose to keep most of our roots crops in the ground, the carrot tops can look a bit ratty but the carrots are good, beetroot, turnips, parsnips and radish just keep on growing. The photos below show some of our mid winter crops.

Cabbages 

Cabbages can be dug up, leaving the stem and roots intact, remove any ratty leaves so there is just a firm head. These can then be hung upside down, put in bins or individually wrapped and put on a shelf. Unless your storage room is very airy in is a good idea to store them away from other foods like apples as their smell can taint other produce. Red cabbages and late crop cabbages are ment to store better, lasting 3 to 4 months or more. 

Low Humidity Crops (Dry Storage) 

Onions 

When the tops start droop, bend them all over and leave for a couple more days, then the onions are ready to be pulled.  Once harvested onions need to be dried before storing, this can be done by leaving them on the ground for a couple of days if the weather is good. Or by spreading them single layer on a rack or the floor in a protected area. Its needs to be warm, dry and breezy so that the skins and neck of the onion dry. Turning occasionally can help speed up the process. Once fully dry trim the roots and necks (if not hanging them), put aside to use first any which are damaged or with green necks. The rest can be stored by hanging in ‘strings’, or in onion sacks, baskets or boxes as long as the air can circulate around the onions. Pungent thick-skinned onions store better than the thin-skinned sweet onions, so choose a variety like Pukekohe Longkeeper for long term storage. Onions should store for 5 to 8 months. 

Garlic 

We harvest the garlic when the leaves are 50/50 dry/green, check a couple of bulbs and if they are a good size harvest before the cloves start to separate. Brush off any loose dirt and spread out to dry in a shady dry airy place, turning occasionally, or after a couple of days tie in loose bundles and hang till fully dry. Once dry the garlic can be plaited or trimmed and stored in baskets or boxes. Garlic can be easily stored for 5 to 8 months, but should last a year or until you harvest the next seasons crop, though it may start to deteriorate. If you see cloves starting to sprout or wrinkle use these ones first and remove any which are breaking down.

Pumpkins 

Harvest pumpkins after the plants have died down but before the first frosts. Leave the stalk on, we generally cut them where they meet the vine. If the stalk breaks off use these ones first as they will not store well. Wipe of any dirt and if the weather is good leave them outside to cure, this hardens the skin, heals any wounds from harvesting and lets them ripen and develop more flavour. If the weather is not good put them in a warm spot for up to 2 weeks. Once cured move to a cool dry place and store on wooden shelves, an old wire-wove bed base, cardboard or hang in nets. Pumpkins be stored for at least three to six months. Choose varieties which are especially for long storage such as the tough skinned ‘Ironbark’ pumpkins like Triamble, Queensland blue and Marina di Chioggia

Squash, Kamokamo and even mature marrows can be stored this way too. 

Kumara 

Only store undamaged kumara and once dug spread them out in a cool airy place to let the skins cure for a week or so. It is better not to wash them as you want the skins to stay dry once harvested. Then move to a dry dark place, kumara can be layered in boxes with paper, straw, hay, sawdust, silver fern or bracken fronds between the layers or wrap each one individually in paper. Dampness must be avoided or they will rot. If stored right they should last 4 to 6 months, try to avoid really low temperatures, 12 to 18 °C is preferable.

Yams (Oca) 

Yams can be stored at room temperature for several months. For longer storage choose the best tubers and store in dry sand, sawdust, or in between layers of bracken or hay etc in a cool dark place. Yams can be stored for about 5 to 6  months or more. 

Fiona Sutherland’s Root cellar. 

This is an example of a root cellar in Wairarapa, New Zealand, made from a concrete tank. Fiona explains how they have made it…

“Essentially it is a concrete tank 1800mm high x 1600mm wide, with some tweaks buried into a bank and then topped up. We aimed for 3m underground. It has two vents, one pipe to the bottom for air in and one at the top for air out. 

There are 6 x 100mm wide holes in the bottom so as to have a connection with the earth, supposed to produce a better outcome so they say. A refrigerated door to keep it cool. 

So far, we are tracking well at 95% humidity and 6C, it takes time for the concrete to cool down so we are sure we will get down to 4C. The timber shelving is being made.” 

For more food storage ideas check out our other articles…  

Lard in the Larder 

The Meat Safe and Alternative Refrigeration 

Sorting the Pantry or ‘Dry Larder’