Bean

Light and exposure

The bean wants sun and warmth. Set aside a well-lit, open bed for it, sheltered from the prevailing cold winds that snap the young stems. The spot that catches the midday sun, or a warm corner of the kitchen garden, gives it the best growth.

Climbing varieties easily reach one metre fifty or two metres. Place them so as not to shade the rest of the kitchen garden, along the side of the bed where their shadow does not fall on the lower vegetables, so that those keep their light.

Watering

The bean needs regular water above all at flowering time and when the pods form. A lack of water at this stage makes the flowers drop and gives short, stringy pods. Water at the base, without wetting the foliage, preferably in the evening in summer.

Before flowering, stay sparing: an excess of water on a young plant favours foliage at the expense of flowers. A light mulch at the base keeps the soil cool during the dry spells of high summer.

Soil and repotting

The bean is not demanding, but it likes a loose, light and well-drained soil, neither too heavy nor waterlogged. Avoid fresh, nitrogen-rich manure: like all legumes, it fixes the nitrogen from the air itself thanks to the bacteria on its roots, and an excess of nitrogen makes leaves grow instead of pods.

Soil that is too cold and wet is its worst enemy at sowing. Wait until it warms above 12 degrees. In the region’s heavy soil, a slight earthing-up or a raised bed helps the soil to dry out and warm up faster in spring.

Temperature and humidity

The bean is decidedly frost-tender. The seed does not germinate below 10 to 12 degrees in the soil, and the slightest frost kills the plant. It is a summer vegetable that needs warmth to come up fast and grow without a check.

Where summers stay temperate, cold is the factor that governs the whole calendar. Nights stay cool late into spring, and a late frost is not rare. So never sow before the last frosts have passed, and often it pays to wait two or three weeks more to be safe. At the other end, the first autumn frosts put an end to the harvest.

Pruning and upkeep

The bean is not pruned, but climbing varieties are trained. Set up poles, netting or supports right at sowing so that the twining stems catch onto them by themselves. Help the first shoots find their support if needed, then they climb on their own.

For dwarf beans, a light earthing-up at the base when the plants are about fifteen centimetres tall steadies them and stops them keeling over under the weight of the pods. Pinch the tip of the poles once they have reached the top of the support, to focus the plant on production rather than on height.

Pests and diseases

The bean fears above all the diseases linked to humidity. Anthracnose (Colletotrichum lindemuthianum) marks the pods with brown ringed spots, and halo blight, a bacterial disease, leaves oily patches on the leaves. Both spread in damp weather. Never touch wet foliage and space the plants well so they dry quickly.

As for pests, slugs devour the young shoots at ground level, especially in a damp spring, and black aphids sometimes colonise the top of the stems. Harvest and remove diseased pods, and practise rotation by not putting beans in the same spot again for three years.

Propagation

The bean is sown directly in place, never transplanted. Sow in clumps of five to six seeds every forty centimetres, or in a row spacing the seeds eight to ten centimetres apart, three centimetres deep. Water well after sowing and wait for emergence, a good week in warm weather.

To harvest your own seed, let a few fine pods dry completely on the plant at the end of the season, until they turn parchment-like. Shell them, let the seeds dry for a few days in the air, and keep them dry for the following year. The bean reseeds very well from one year to the next.

Toxicity

Raw pods and dry seeds contain phasin, a lectin that makes you ill. The green bean is always eaten cooked, never raw.

Month-by-month care calendar

Green Hub tips

• Never sow before the last frosts have passed: the bean is frost-tender and its seed rots in cold, wet ground.
• Pick often and young. The more tender pods you gather, the more the plant flowers and makes again.
• No manure or nitrogen fertiliser: the bean makes its own nitrogen, an excess gives leaves instead of pods.
• Sow a new row every two to three weeks, stopping about ten weeks before your first autumn frosts, to harvest fresh beans all summer.