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How to Grow Common bean

Phaseolus vulgaris · Also called: bean, beans, dry bean, dry beans, haricot bean, kidney bean, navy bean, pinto bean

A young common bean plant in a pot showing several trifoliate leaves, each made of three broad pointed leaflets on one stalk.

Photo: Datadoggieein, CC0 (Wikimedia Commons)

The common bean is the most important food legume eaten directly by people anywhere in the world. It is a top-ten crop in 52 of the world's 195 countries, and it is the single biggest crop of all in four of them: Burundi, Djibouti, Haiti and Rwanda. For millions of families it is the only protein they can afford, and it is grown mostly by small farmers, often by women, on small plots, by hand. It is also the crop that quietly feeds the soil, because it makes its own nitrogen and leaves some behind for whatever you plant next.

Global Importance

The common bean is the most important food legume eaten directly by people anywhere in the world. It is not a rich country's crop or a poor country's crop. It is grown in the Andes, across eastern and southern Africa, through Central America and the Caribbean, and across South and Southeast Asia, almost always by small farmers on small plots.

Growing Common bean, Stage by Stage

  1. 1. Get the land ready — Loose, clean, well-drained soil. Not fine dust, not hard clods. Beans need air at the root more than most crops.
  2. 2. Choose your bean type and your seed — Two decisions, in this order. Bush or climbing. Then which colour of bean your market actually wants.
  3. 3. Plant the seed — Straight into the ground where it will grow, into warm moist soil, not too deep, in rows you can walk between.
  4. 4. Water — Steady and moderate. Beans want damp, never soaked. And there is one week you must not let them go dry.
  5. 5. Weeds and feeding — Weed early and twice. Feed the soil, not the leaves. And understand what the lumps on the roots are doing for you.
  6. 6. Watch for pests, week by week — Different animals attack at different moments. Know which week to look for what, and you will catch nearly all of them in time.
  7. 7. Watch for disease, week by week — Almost every serious bean disease arrives inside the seed or waits in old plant rubbish. Clean seed and clean fields beat every spray.
  8. 8. Know when to harvest — There is a narrow window. Too early and the seed is soft and will not keep. Too late and the pods split and throw your crop on the ground.
  9. 9. Thresh, dry and store it so you do not lose it — More beans are eaten by weevils in stores than by any pest in any field. This stage is where a good crop is kept or thrown away.

Common Problems & Troubleshooting

If you see: Young seedlings in the first month wilt and die for no obvious reason. The stem just above the ground is swollen, cracked or split, and the lowest leaves have turned yellow. Splitting the stem lengthways shows a small white maggot, or a brown or black case, under the skin.

It likely means: Bean fly, also called bean stem maggot. A tiny shiny black fly laid eggs in the young leaves and the maggot tunnelled down inside the stem to the roots, cutting off the plant's food supply and killing the taproot.

Do this: Heap soil up around the base of every damaged plant that is still alive. The plant then grows new roots above the damage and can pull through.

If you see: Small raised reddish-brown or rust-coloured bumps scattered over the leaves, and sometimes on the pods and stems. When you rub them with a finger, a rusty powder comes off onto your skin. Badly hit leaves curl upward, dry and fall, and the whole field looks scorched.

It likely means: Bean rust, a fungus that needs more than about ten hours of water sitting on the leaf to get started, so it follows dew, cloud and cool moist weather.

Do this: Use the rub test to be sure. Rust powder comes off on your fingers. Bacterial blight and leaf spot do not.

If you see: Dark brown to black lines running along the veins on the underside of the leaves. On the pods, sunken spots ringed by a slightly raised black circle with a reddish border. Young pods shrivel and dry early, and the seed inside is discoloured and misshapen.

It likely means: Bean anthracnose, one of the most damaging bean diseases in the world. It is worst in cool to moderate weather with frequent rain and high humidity, and it came into your field inside the seed you planted.

Do this: Do not save seed from this crop under any circumstances. The fungus gets right inside the seed coat and will plant itself again next season.

If you see: Water-soaked spots that appear first on the underside of the leaves, then join up into large irregular brown patches edged with a narrow yellow band. General yellowing follows. Pods carry sunken circular spots with a narrow reddish-brown border, and in wet weather a yellow slimy ooze dries into a crust on them.

It likely means: Common bacterial blight, favoured by warm to hot weather with high humidity. Like anthracnose, its main source is the seed, and even a trace of infected seed can infect a whole field.

Do this: Do not save seed from this crop. Get clean seed for next season.

If you see: Leaves patterned in patchy light green or yellow and dark green, puckered, curled downward and distorted, on plants that are noticeably shorter than their neighbours. The affected plants flower late and carry fewer, smaller pods with fewer seeds. In some varieties the young leaves develop diffuse reddish-brown areas with black veins, and the tip of the plant wilts and dies back.

It likely means: Bean common mosaic virus, or its more damaging relative bean common mosaic necrosis virus, which causes that black-veined form. These are the most important bean virus diseases in Africa. The infection arrived in the seed and aphids are now spreading it plant to plant.

Do this: Accept honestly that there is no cure and no spray for a virus. Nothing you buy will fix an infected plant.

If you see: Plants that yellow from the bottom up, wilt and die in patches across the field, often in the lower or more compacted parts. Pulled up, the roots are few, brown and rotten. The lower stem may show reddish-brown streaks and cracks, or sunken dark cankers with brown edges, or a fan of silky white mould with small round seeds of fungus at the soil line.

It likely means: The bean root rot complex. Several different soil fungi cause it and they usually arrive together. It is really a disease of stress: poor soil, compacted soil, acid soil, waterlogging, drought, or land that has grown beans too many times.

Do this: Improve the soil first. Well rotted farmyard manure, compost or green manure does more against root rot than anything you can spray.

If you see: The plants look healthy and green and flower normally, but the flowers dry up and fall off without setting pods. The pods that do set are short, with two or three seeds instead of five or six. This happens most in very hot weather or during a dry spell.

It likely means: The crop was stressed at exactly the wrong moment. Beans abort their flowers under heat and under water shortage, and flowering plus the two weeks after it is the most sensitive fortnight in the whole crop.

Do this: If you have any water at all, use it now. Watering at flowering and pod fill is worth more than watering at any other time.

If you see: Neat round holes in the stored beans. Small beetles crawling in the sack. Fine powder like flour at the bottom. Sometimes tiny white egg shells glued to the outside of the seeds. The beans get lighter and lighter and eventually there is more dust than food.

It likely means: Bean weevils. If the eggs are glued onto the seeds with the shells left behind, it is the Mexican bean weevil, which starts and multiplies in the store. If not, it is more likely the common bean weevil, which laid its eggs out in the field in pods that had already split open, and came home with your harvest.

Do this: Take the beans out, dry them hard in the sun again, and sort out every holed and damaged seed by hand.

Yield & Market Value

Growing the crop is only part of the job. The last part is knowing what a normal harvest looks like, and knowing what your beans are worth, and in which grade, before you agree a price with anybody.

Remember It This Way

If you forget every other page of this guide, keep these lines. They are the whole crop, in order, short enough to carry in your head.

Test Yourself: Identification

This leaf is of which plant?

This leaf is of which plant?

Why should you turn a bean leaf over, and what are you looking for underneath?

Why should you turn a bean leaf over, and what are you looking for underneath?

Which crop is this, and is it a bush type or a climbing type?

Which crop is this, and is it a bush type or a climbing type?

Honest Limits of This Guide

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