Often the problem is not of growing a crop but of having it when you want it. The majority of our crops come in summer and autumn, as is their way. Most plants find it preferable to flower and fruit within the annual growing period. (A few are more difficult, of Mediterranean origin, used to milder winters they endeavour to carry fruits through the colder months to ripen the following year. Thus olives, loquats, lemons and oranges and so on are inherently rather difficult.) Anyhow the bulk of our crops, especially the vegetables, grow from spring through summer to be harvested in the autumn. These then have to suffice for almost a year before more become available, or substitutes have to be found.
When gardening is just a hobby, for relaxation and pleasure, then it does not matter if your stored crops run out early. They may not be quite as good but there are plenty of replenishments available at the supermarket. But with increasing food prices and world shortages it may, suddenly, become necessary to provide for ourselves more of the time. As I said at the beginning; the problem is not of growing the crop but of having it when you want it. Storage is essential- and good storage greatly extends the useful life of the harvest. Most crops may remain edible but become unpalatable with poor storage becoming tainted, withered or losing texture. And unfortunately each crop has a somewhat different set of requirements for good storage. Thus although at a push you can keep apples, pears, potatoes and onions all together in one place they will not last as long or taste as good as if you keep them all separately in more optimum conditions.
The first and most important factor for storing anything though is condition- in general everything must be near perfect as any bruise, rot or blemish will soon deteriorate and may lose not just the damaged item but all those around it. Do not try to store anything in poor condition, better to process it instead into frozen, dried or pickled or whatever.
The second most important factor is security- that is freedom from rats, mice, birds, squirrels or anything else that might rob or damage your stores. I find dead deep freezers make very good stores for many sorts of crop being metal inside and out and well insulated. Given space each crop can have it’s own freezer so they do not cross contaminate, or crops can be combined if kept separate in plastic bags or wrapped in paper. An alternative is to bury a plastic dustbin in a cool shady spot that won’t flood. This makes a very good root cellar or apple store especially if covered with rain excluding layers of extra insulation. A dry, pest proof shed or garage makes a good store for many crops, and can also house crops stored in dead freezers giving them an extra level of frost protection. Old cupboards and sets of drawers can help accomodate boxes and trays of different crops separately and more securely. Wrapping in paper or interleaving shredded paper helps cushion items and mops up any oozings from the inevitable rotters. And don’t forget the labels.
Some crops such as onions and squash need plentiful air though so they can’t be sealed up and need keeping on wire trays, baskets or netting- the last can be stretched over frames. I find a good container for bulky items are recycled baker’s bread trays which are made from strong latticed plastic and stack well. Be careful with items stored in sheds especially on trays as rodents will soon find them unless well protected with traps. Seed crops either for eating as with haricot beans and celery seed or for sowing need careful drying and then keeping in paper bags somewhere very dry and secure. Sealing them in tins or jars as an extra precaution or again keep them in a dead refrigerator- but include some moisture absorbing bags of silica gel to keep it dry not stagnant.
Of course some crops can be left unharvested till required.This works well in mild winters as they stay freshest thus. However if it turns really cold then it kills many plants and solidly freezes the root crops into the ground so digging becomes impossible. Most years though leeks, Brussel sprouts and Savoy cabbages are fairly safe left where they are grown. Even so they may need a bag of straw or shredded paper putting over them if conditions threaten to be harsh. Root vegetables such as carrots, parsnips, salsify, scorzonera, and Jerusalem artichokes are best left in the ground but covered with insulation such as straw and a plastic sheet so they can still be dug if it freezes hard.
Other roots such as turnips, Swedes, beetroot, Kohl rabi and winter radish are better stored in a dead freezer or similar. These roots need some moisture to prevent shriveling but if wet may rot so they are often packed in sand or similar in bags or boxes before being put in the store. Never ever wash anything before storing- gently rub off lumps of dirt instead but do not abrade the skins.
Cabbages can at a push be stored with roots though to prevent taint they are better in a store of their own. Inevitably there may be slugs in the roots, and if these crops are combined the cabbages will suffer. One way of reducing the damage is to wrap the cabbages in newspaper previously soaked in salty water as cabbages tolerate the damp while the saltiness stops slugs moving around. Another is to put slug pubs; saucers or jam jars of fermenting beer or fruit juice, in amongst your stores.
Potatoes are an important and big crop needing careful storage as they can keep till early summer. They need to be kept cool but warmer than the other roots or cabbages as if they get chilled to anywhere near freezing they become sweet whereas cold does not harm the others. Harvest them on a drying day and let them have an hour or three in dappled shade to toughen their skins before grading and storing. Potatoes will sweat and rot or sprout so are best packed in paper not plastic bags if they are to be simply stood in a frost free place such as a garage or shed. But for longest storage I keep them in plastic trays in a dead freezer under cover. Here they can be kept just that little bit less dry so they do not wither so soon. In very harsh weather persisting for days there is a chance that they could freeze even in an insulated box such as a dead freezer or a buried dustbin. However by the simple expedient of putting in plastic bottles of warm water the temperature can be prevented from dropping too low. And likewise the potatoes can be kept cooler to prevent sprouting in spring by thawing plastic bottles of ice in with them.
Sweet potatoes are very different. Once dug they need to be dried in a very warm place and then kept warm and dry, even so they do not keep easily. So I find they are simpler grown in big tubs which are dried off, compost and plants together at the end of the season and then stored untouched in a warm dry place until required. Tomatoes are much the same. They keep best on the vines, uprooted and hung upside down in an airy warm shed. They can be picked and kept in trays or drawers instead.
Onions, garlic, shallots, and marrows, squashes and pumpkins all like it warmer and dryer but airier. Indeed these all do well suspended in nets in the roof spaces of warm dry sheds or airy garages. It is hard work and counterproductive to string or even bunch onions or garlic as they may rot where they are congested. Better to spread them out thinly somehow. If no dry roof space is available then all of these can be stored stacked in trays. Marrows and squashes and similar need plenty of air all over and do not like standing on anything cold or damp as they bruise and rot where they touch. Taught soft net trays are good but pushed into tights and suspended in the roof space is better. If they are packed or laid on anything solid then use shredded newspaper or cork or similar to gently pad them.
The fruits, mostly apples and pears, require even more care to keep out rodents than for the other crops so far. These should not be mixed together though, nor with quinces as they taint each other. Neither should early and late storers be mixed as they then tend to ripen together. Too much air and they wither, too little airflow and they go off. And pears need it much warmer and moister than the apples. However it is easy in practice. Apples are best packed in trays or boxes, ideally filled with shredded paper, I use buckets. These are then stood in a cool dry place. A dead refrigerator in a shed or garage works well for a few trays or a dead freezer unit for bulk. In either case perforate the door seal with holes to allow air to flow but not big enough to let mice in.
Pears for short term storage are best on trays where they can be kept in a warm moist place- kitchen or bathroom maybe as it is important to inspect daily as pears ripen and go over fast. However the longer keepers, mostly for cooking, keep well packed in boxes or buckets of autumn leaves and stood in a cool shed or yet another freezer body.
Then there are the nuts. Hazel and Cobs once dried need their husks removing and then store well for a year or more in their shells if packed in sand or salt. But use tin boxes or glass jars as rodents and squirrels will sniff them out and have them otherwise. Walnuts and chestnuts also need husking and drying but are best kept in nets hung in a secure dry place or brought into the living room and used as they do not keep so long so well as hazels when packed in salt.
And do not forget your seed crops- peas and beans keep well pulled with the haulm and hung in a dry roof space though they may be robbed. Sweet corn can be dried on the plant and then the kernels rubbed off, dried further and packed in paper bags. Likewise all small seeds such as celery and parsley are better dried and stored in paper bags somewhere secure.