I doubt there is a vegetable plot in the country that does not grow some beans, however almost invariably these are grown for fresh use and more rarely for their dried seeds. Yet how simple to grow a few more plants and leave these to dry providing stores for winter use when the fresh are but memories.
Almost any edible bean can be dried for later use, indeed the vast majority of beans have always been so used. The common, field, horse or tick bean still grown for animal feed, is ancient. This was a staple food for many peoples for millennia though the Greeks, rightly, noted that in some cases, especially for people of Mediterranean origin, a diet of beans caused a blood disorder (favism) and vision problems. Our Broad beans are descended from these ancient beans and still carry a small risk which is negligible for most of us. Likewise many related beans, and other legumes, can cause similar reactions and care must be taken never to eat their raw seeds (or pods or foliage) but only well cooked ones. Red Kidney beans have even proved fatal if not boiled for long enough to break down the poisons!
However do not worry unduly; as long as beans are cooked well they are excellent foods full of nutrition. The dried beans keep exceedingly well and are probably the least effort of all crops to grow and harvest. Of course some dried beans occur sporadically as it's hard to spot all the pods when picking but if a whole row or bed is planned then some effort should be made to help the drying process. Airflow is crucial so put a bed of beans for drying where it will not be surrounded by tall crops or barriers -a stagnant spot will result in mouldy beans -not only a loss but a much more serious health threat! Also give the plants much more space than you would for fresh beans to ensure a full crop can be held as well as help the airflow and ripening. In wet autumns provide a rain proof roof to help dry the crop but do not 'box' the plants in or they will rot!
Once they start to wither and fade the plants are best pulled and then hung upside down on lines under cover in a dry airy place to finish. Either for food or seed the beans keeps best in their pods, the fully dried pods can be left on the dried up haulm and tied in bundles and hung in a dry place -an attic is ideal. There they will keep for years however losses to rodents will occur unless you take precautions. Alternatively pack the dried pods in a tin or secure box, or shell the beans out and keep them in paper bags in jars or tins. As an emergency food for famine there is little better or longer keeping.
However dried beans are also a gourmet food and the basis of so many great dishes such as cassoulets and bacon & beans. In all cases the dried beans should be washed and sorted removing broken, mouldy and shrivelled ones. Then they should be soaked overnight, the water changed and soaked again, and then they must be thoroughly well cooked -at the least boiled for half an hour. Luckily bean dishes almost invariably taste better the longer they are cooked and are often even better when re-cooked on following days.
There so many types of bean and almost all of them can be dried but some are far more suited than others. The Broad bean can be dried and always used to be, indeed is still sold in North Africa where it is used much like chick peas to make a hummous. Once soaked and boiled these are excellent if forgotten fare. Sow Broad beans further apart than usual to get a crop of larger dried beans. Preferably sow in blocks so they can be tied around to stand up better for longer. Once a good flower set is achieved stop the stem tips to prevent aphids. Then as the pods start to swell thin the number of pods taking some as soon as their beans are large enough to eat. As these are so early and vigorous legumes I use them as nurse crops come windbreaks around other crops so surplus are often had by accident. And if you overlook a crop that gets away from you then take just the tenderer beans and leave the toughies to be a dried crop rather than eat them up in such a state! (small immature broad beans are not awfully nice as bitter though the whole young pod is often cooked and eaten)
As Runner beans are notorious for producing a surplus it seems sensible to learn to appreciate these as a dried seed. Runner bean seed is only commonly eaten when immature and sliced up within the pods. However once soaked and skinned these large seeds are much like Butter beans especially the white seeded varieties such as Csar which are really worth growing just for drying.. As these are so tall they get plenty of air and ripen and dry easier than most other beans, indeed they do it anyway if you don't prevent them. They do need firm support to hold a good crop and do better on wire or canes than string and need stopping by nipping the tips out when they reach your height limit for picking. I once took some Scarlet Runner seed to a French friend in Beaujolais, the following year I was presented with a soup of the new bean seed crop, it was delicious -he then showed me the plants -they were twice the height of his steps, a good fifteen feet high -it shows how this crop loves plenty of sun as well as water!
Of course not all running beans are runners and I find the Running French beans to be a very productive crop. Not as vigorous and demanding as Runner beans, and more fertile and productive in drier conditions. In East Anglia the dry summers mean true runners need a lot of extra water just to set. However the running French beans need water to give a bigger succulent crop of fresh beans but can throw a small crop of dried beans easily with no extra water at all. Ones such as Blue Lake white seeded are excellent as Haricot seeds. The Borlotto varieties come from Italy and are similar but rather more tender as are the Tepary and Mexican Black sorts. The Pea bean is another sub variety also climbing but with a rounded bean, this is not really exciting fresh but is OK dried for soups and stews.
The dwarf French beans are the classic for Haricots. Although these are tricky to get off to an early start as they resent cold soils and winds once growing they are easy. For dried beans an early start is not essential so these can be sown more at leisure in warmer soils well after the last frosts. Later sowings come up reliably so space drying varieties well apart -after all they won't be picked to keep on cropping as with the fresh sorts. Of course almost any French bean whether for eating as the green pod, the green bean or the drying varieties can be dried and used as Haricots. However the small ones and some others have rather too much and too tough a skin for palatability and digestibility though those with white skins are usually more acceptable. But it is really much better to grow the proper ones. The standard is Brown Dutch which is a good reliable cropper of baking beans for winter dishes. Horsehead is another good one and the very youngest pods can be eaten cooked thus thinning the crop and giving slightly bigger seeds. Comtesse de Chambord is another famous one with white seeds. For years I had an excellent very creamy yellow heritage bean called Hutterite soup but I lost my seed to the pot this last winter by greedy accident.
The drying French beans do need more care than the climbing or broad beans as they are ripening late in the year close to the muddy ground. Thus to prevent gritty diseased pods they may be taken up earlier once approaching maturity and finished off under cover. Cut the roots off with secateurs to save taking soil with the haulm, tie the plants in small bunches and hang them in a very dry airy place. Shell out or save in the pods but keep them somewhere dry and rodent proof!
Soya beans are another possibility in sheltered warmer gardens. They really need a cloche to start off with and a long growing season. The drying varieties are left to mature fully and the beans dried off under cover if necessary before shelling and cooking or turning into flour, 'milk', tofu etc. They are poor doers in average summers. Likewise with Red kidney beans, Chick peas, Lentils and the true Butter bean.
Of course one other closely related and easier crop, peas, can also be treated exactly the same, indeed the effort of picking podding and freezing peas is so excessive I grow some batches just to dry and thresh. The dried peas need soaking overnight but are excellent all winter and my hens love scratching up the haulm for ones I've missed. The Marrowfat round seeded varieties are the traditional drying pea but I've found any sort is good if all you want are some for soups and stews.
Oh yes- and that barometrically challenging feature; beans are justly infamous for causing windigestion. All beans seem to display this feature though some varieties, and some people, are worse than others. There have even been breeding programmes to find less flatulent sorts, with little success. To be fair; although unpleasant, uncomfortable and antisocial it must be pointed out that some wind may benefit your plumbing by 'loosening up' tight spots and blasting things through. But if you really don't enjoy this liberating experience then use generous amounts of summer savory with your beans, the flavours go well together and the savory will take the pressure out of your sails.