Vegetable · Fabaceae
Green Bean
Phaseolus vulgaris
Sow them in warm soil and green beans hang slim pods by the handful all summer.
Full sun
Every 2–7 days
61–84°F · 16–29°C
50–65 days
Overview
Green beans are one of the easiest crops a beginner can grow, and they carry the slim green pods most people picture at the word bean. The plant belongs to the legume family and traces back to the Americas, where people have grown it for thousands of years. Set the seed in warm soil and it rises into a fast, generous plant hung with tender pods.
Two forms shape how the plant looks. Bush beans hold a low, compact mound of broad green leaves and ripen most of their pods in one short flush. Pole beans send twining stems climbing for weeks, wrapping a support in green and dangling pods along its length right through summer.
The plant feeds itself from within. Down among the roots, bacteria pull nitrogen straight from the air, so the plant grows on poor ground that would starve other crops. Watered through flowering and picked while the pods are slim and green, it keeps hanging out new ones for weeks.
Care
The short version: full sun, warm soil, and steady moisture once the flowers open. Sow the seed where it will grow, keep the fertilizer light, and pick the slim pods young and often to keep more forming.
Light
Beans want full sun, at least six to eight hours of direct light a day, to fill out their pods. In shade the stems stretch pale and leggy and the crop comes thin and late.
Water
Beans take about 1 inch (2.5 cm) of water a week, with the soil kept evenly moist while the flowers open and the pods swell. Water goes to the base and off the leaves, since wet green foliage is where rust and other diseases settle in.
Soil
Beans grow in well-drained loam dark with organic matter. A pH of 6.0 to 6.8 suits them, a touch acidic, and loose, crumbly ground keeps the seed from rotting before it sprouts.
Temperature
Beans do best between 61°F and 84°F (16°C to 29°C). Warm soil is what wakes the seed, and a late frost blackens young plants, so an early start gains nothing.
Humidity
Ordinary outdoor humidity suits beans, so there is no number to reach. Airflow matters far more than the level itself, since a crowd of damp green leaves is exactly where rust and other fungal problems take hold.
Feeding
Beans make their own nitrogen and take almost nothing. A light dose of balanced fertilizer at planting is plenty, and a heavy hand only piles on leaves in place of pods.
Pruning
Beans need no routine pruning. Any spotted or diseased leaf is pinched off, and frequent picking of the slim pods keeps the plant setting more.
Size & spacing
The plants stand 1 to 10 feet (30 cm to 3 m) tall, low and mounded as bush types or tall and twining as pole types. A spread of 8 to 18 inches (20 to 46 cm) gives each plant the room that lets air slip between the leaves and keeps disease down.
When to plant
Green beans are warm-season plants with no tolerance for frost. The seed waits until the last frost has passed and the soil has warmed, then goes straight into the garden. Slim tender pods are picked every few days through summer, and the plant keeps hanging out more.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: After last spring frost when soil has warmed to at least 60°F
- Harvest: Harvest immature tender pods through summer, picking every few days
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Most bean trouble marks the leaves or the pods, and a close look usually shows what it is. Match what you see below against the cause. Catching a spot or a lesion early keeps a setback from running down the row.
Leaves eaten to lacework with larvae beneath
Leaves reduced to a fine green lacework, with only the vein network left standing, are the work of the Mexican bean beetle. Its copper-colored adults wear black spots, and its spiny yellow larvae cluster on the leaf undersides beside bright yellow egg masses. Picking off every adult, larva, and egg mass thins them out, and clearing the spent plants after harvest strips away the shelter they would otherwise overwinter in.
Fix:
- Handpick adults, larvae, and egg masses
- Apply approved insecticide if infestation is heavy
Rust-brown pustules speckling the leaves
Small raised pustules in reddish-brown to rust colors, dusting the leaves and smudging powdery spores onto a fingertip, are bean rust. As the fungus takes hold the green fades to yellow and the leaves fall away early. Stripping the most spotted leaves, spacing the plants so the air keeps them dry, and watering low at the base all work against it.
Fix:
- Remove and destroy infected foliage
- Apply a labeled fungicide if severe
Blossoms falling before pods form
In heat past roughly 85°F to 90°F (29°C to 32°C) during bloom, the small bean flowers loosen and fall, leaving bare stems where pods should swell. This is heat stress, not a pest or a disease on the plant. Even soil moisture carries the plants through, and the flowers hold and set pods again once the air cools.
Fix:
- Maintain even soil moisture
- Wait for cooler temperatures to resume pod set
Dark sunken lesions pitting the pods
Circular lesions that sink into the pod surface, rimmed in dark tissue and sometimes weeping pinkish masses of spores, are anthracnose. The fungus rides in on infected seed and moves plant to plant through wet foliage. Pulling and destroying the marked plants and pods clears it, and their seed is never kept, since the fungus travels inside it.
Fix:
- Remove and destroy infected plants and pods
- Do not save seed from infected plants
Toxicity
Green beans are a safe, edible crop, and the growing plant poses no poison risk to people or pets. The slim green snap pods are good raw or cooked, and cooked beans are a common treat for dogs. The one thing to keep in mind is that mature dry seeds need cooking before anyone eats them, since raw dried beans hold lectins.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cats come to no harm from green beans. A green leaf or a slim tender pod chewed by a cat carries nothing toxic.
Dogs None
Dogs are unharmed by green beans, and the plain cooked pods, snapped into short green pieces, make a common low-calorie treat.
Horses Safe
Horses are safe among bean plants. Neither the broad green leaves nor the slender pods carry a toxin that would harm them.
Rabbits Safe
Rabbits can crop the leaves and young green pods without harm, though any fresh green suits them best in small amounts.
Livestock Safe
Cattle, goats, and sheep can browse the leafy plants without poisoning, and the standing crop holds no danger for them.
Birds Safe
Backyard hens and other birds can peck the leaves and slim tender pods with no ill effect at all.
People Safe
The crisp green snap pods are eaten raw or cooked. Only the mature dry seeds inside need cooking first, since raw dried beans hold lectins.
Mature dry beans of Phaseolus contain lectins (phytohaemagglutinin) and should be cooked before eating, but tender immature snap pods eaten whole are not a pet-toxicity concern.
Varieties
Hundreds of bean varieties exist, but a few dependable names turn up in most gardens. These are the ones worth knowing before you pick a packet.
Blue Lake
A heavy cropper found in both bush and pole forms, bearing round, tender pods that snap clean and pull free of strings.
Kentucky Wonder
A vigorous old pole bean grown for its long, full-flavored, meaty pods.
Provider
An early bush type that shrugs off cool soil, which makes it a sound choice for the first planting of the year.
Contender
An early bush snap bean with smooth stringless pods and solid resistance to common diseases.
Companions
Beans grow well with the crops that share their space without competing, and the three-sisters trio of corn, beans, and squash is the classic example. They sulk next to alliums like onions, which hold their growth back.
Plant near
Corn: Part of the traditional three-sisters planting; corn stalks provide support for climbing beans.
Squash: Three-sisters companion; squash foliage shades soil and suppresses weeds while beans add nitrogen.
Cucumbers: Cited as a compatible companion that grows well alongside beans.
Potatoes: Listed as a beneficial companion in extension companion-planting guidance.
Keep apart
Onions: Alliums such as onions and garlic are reported to inhibit the growth of beans.
How to propagate
Green beans are about as easy to start as a plant gets. They grow from the smooth seed sown right where they will live, since they dislike being moved.
SeedEasy
Direct-sow after the last frost once soil reaches at least 60°F · Seedlings emerge in about 7-14 days under warm conditions
The smooth bean seed goes straight into the garden once frost has passed and the soil has warmed to at least 60°F (16°C). Beans resent having their roots disturbed, so transplants are skipped, and cold, wet ground rots the seed before it can sprout. In warm soil the folded seedlings push up in about 7 to 14 days.
Myths
Green beans must be soaked or cooked before eating, just like dry beans.
The soak-and-cook step belongs to the hard mature dry seeds, which carry lectins that only heat breaks down. The slim green immature snap pods are safe raw or lightly cooked, so the dry-bean warning has no bearing on the tender pods pulled off the vine.
Beans need a heavy dose of nitrogen fertilizer to crop well.
Inside their roots, beans host rhizobia bacteria and fix their own nitrogen from the air. Feed them heavily and you grow a dense mass of green leaves with few pods hanging beneath, so a light feed at planting is all they take.