Why grow beans at home? It’s easy, they’re great for your health and good for the planet | Gardening advice

It was in a food market in Oaxaca, Mexico – and after eating a particularly memorable plate of black beans with waxy, yellow potatoes at the end of a day’s hiking in the mountains – that Susan Young found herself falling hard for beans. She had seen them growing in fields and sold dried, and witnessed how embedded the bean was in Mexican culture and cuisine. So she bought a few back home to Monmouthshire – and before she knew it, a few beans turned into an obsession.

Young grows beans in her garden specifically to shell and eat either fresh, as demi-sec (semi-dried, with a unique flavour) or dried. She favors varieties from Europe: cassoulet beans from France, the borlotti of Italy, the mongeta and alubias from Spain, brown beans from the Netherlands, mottled beauties from southern Germany and cherry types from eastern Europe. She is so passionate about the power of the bean to change our diet and help the environment that she has written a book on the subject, guiding us from sowing to harvesting and cooking.

Beans are very good for your health. They are an appreciable source of protein (25-29%, depending on the variety); they’re rich in soluble and insoluble fiber, which promotes digestive health, and they’re packed with vitamins and minerals, notably iron and B vitamins. White beans are full of calcium, making them excellent for vegans. All of these things together make for many health benefits, from helping prevent heart disease, colon and bowel cancer to helping maintain low blood sugar levels.

And they are good for the planet, too. Bean plants work with the soil bacteria to fix atmospheric nitrogen, which plants can’t access, into a form that plants can use. In short, they make their own plant food, which means that they can be grown in low-nitrogen soils without additional fertilizer. If you leave the roots in the ground, rather than digging them up after harvesting, any leftover nitrogen will be released back into the soil.

Around the world, shelling or dried beans are an important – and ancient – ​​staple crop. It’s thought that beans were domesticated about 7,000 years ago in South America. Beans have been passed along indigenous trade routes and taken by colonial invaders across seas, then handed down through generations to create a great diversity of pulses.

They run the gamut of size, shape and color as well as flavor and texture: beans that taste almost meaty, are spicy or delicate, keep their shape when boiled, and those that blend into soups and stews.

Beans fall into two main species: Phaseolus coccineus, which we know as the runner bean; and Phaseolus vulgaris, the French bean. Traditionally in the UK we grow both, but we’ve always stopped short of growing them to maturity, eating only the immature green bean. We seem not to have had a tradition of dried beans (other than broad beans and peas).

Finally, they are very easy to grow. There’s still enough time this spring: you can sow into the beginning of May with the aim of planting out by June (any later and you risk the beans not fattening enough).

You can sow direct, but if there are any mice around, they’ll eat the beans before they germinate. Sowing in small, 9cm pots means you can keep them somewhere safe until they have germinated, by which point the mice have lost interest. Sow two seeds per pot; when both seedlings are up, remove the weaker one. If you are somewhere cooler, it’s worth pre-warming the soil with plastic sheeting or cloches for at least two weeks. So, after sowing seeds, cover the soil where you’ll plant out.

Beans grow well in containers and pots as long as they are deep enough for their substantial root run: something the size of a dustbin. Seeds germinate at 15-25C in eight to 10 days, so it often makes sense to sow indoors if the weather is erratic. Plant out when all chance of frost has gone and the plant has two sets of true leaves.

If you’re short on space, or growing somewhere exposed or windy, concentrate on dwarf varieties, which ripen quickly. Tall beans will need something to climb up – a tipi, a bean row or a pergola. Spacing between plants is important for two reasons: so the plants’ deep roots aren’t in competition and get adequate moisture for good swelling; and for air circulation around the beans, necessary for good drying. Dwarf beans should be planted 15-30cm apart in blocks: the larger the bean, the more space the plant needs. Climbing beans need more like 30-45cm between them. All varieties need sunny spots and dislike heavy, wet soils. If you have the latter, plant on mounded soil to improve drainage.

All beans can be eaten as green beans first (though some taste much better than others), then as fresh shelling beans and finally as dried. Fresh shelling beans are to be flavored as the flavor is exquisite: borlotti or Greek giants beans, for instance, are delicious simply boiled and dressed with lemon, salt and olive oil. Harvest when the beans are well developed but the pods are still green. They will cook quickly, like fresh peas. Demi-sec beans are when the pods have just started to change colour, but are not yet dry. The beans will take a bit longer to cook, but demi-sec beans freeze very well.

When the pod rattles and is completely dry, you’re well on your way to harvesting dry beans. The beans may need to dry further before storage (you shouldn’t be able to press your thumbnail into their skin), but will store like this for a very long time; they will have to be soaked before cooking. You will need five to seven plants per variety for two people; 10 plants if you want beans to store for winter.

Nine best beans to grow this summer

greek giants are wonderful runner beans with huge, fat seeds; they need plenty of space between plants. They are as excellent fresh as they are dried.

Hungarian rice beans is a very small dwarf variety with beans not much larger than a grain of rice. Thrives in a sheltered, sunny spot. Can be eaten as a green bean, fresh or dried. Best for containers.

Yin yang or killer whale beans, originally from the Caribbean, this dwarf bean has a very good flavor and works particularly well in stews, where it will keep its shape. Can be eaten as a green bean or dried.

borlotto beans (“fagiolo di Lamon”) is the best of the borlotti, with sweet, nutty flavor and dense texture that can thicken soups or be eaten fresh, cooked with no more than herbs, oil and lemon juice. It’s vigorous, but needs a good, long summer to ripen.

Anellino I gave Trent is a dwarf borlotto that is better for smaller spaces or those further north. Excellent green as well as dried.

Beefy Resilient Grex is prolific and reliable, with a deep meaty flavor (hence the name). It’s a dwarf cross between a Gaucho bean and a tepary. It does as well in a dry summer as in a wet one.

Brown Dutch is a vigorous dwarf bean that is very productive. It has small, oval, golden-brown beans that soften easily, with a delicate, slightly sweet flavour. Perfect for soups. Best if space is limited.

Goût de Chataigne d’Echenans comes from eastern France and is a vigorous, early-cropping climber with rich brown, green and purple beans that taste distinctly of chestnut.

Black turtle is a very pretty bean with a deep lilac flower, originally from Mexico. There are both dwarf and climbing varieties; choose the dwarf if you live further north. Can be eaten as a green bean, but best left to mature into inky black beans, which are rich in antioxidants.

Growing Beans by Susan Young (Permanent Publications, £9.95). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply.