Green bean plants are either pole varieties that grow long vines or low-growing bush types. Most varieties are green, but there are also purple, red, yellow, and streaked beans. Green beans are several inches long and either round or flattened in shape. For fresh eating, they are picked young and tender before the seeds inside have fully developed. Most popular varieties have been bred to have stringless pods, but many gardeners prefer the flavor of the old-fashioned "string" types.
Bean plants are annual vegetables that grow quickly and are best planted in spring, as soon as all danger of frost has passed. The flowers appear about two months after planting. Harvest time varies greatly, depending on the type of bean and the desired stage or bean state: snap/green, shelling, or dry.
|Botanical Name||Phaseolus vulgaris|
|Common Name||Green bean, snap bean, string bean|
|Plant Type||Annual vegetable|
|Size||Varies by type; bush beans are generally 2 feet tall and 1 foot wide; pole bean vines can reach 10 to 15 feet tall and about 1 foot wide|
|Sun Exposure||Full sun|
|Soil pH||Acidic (6.0 to 6.2)|
|Native Area||South America, Central America|
|Toxicity||Toxic to humans (undercooked kidney beans)|
How to Plant Green Beans
Beans are generally direct sown in the garden, as they dislike being transplanted. Their roots are shallow and easily damaged. If you want to start beans inside, plant them in biodegradable pots and transplant the entire container into the garden. The most important rule of growing green beans is not to plant the seeds too early. Plant after all danger of frost has passed. Seeds sown too early may rot in cold, damp soil, and the plants need warm weather to thrive.
Plant the seeds 1 inch deep and be sure to water the soil immediately after planting and then regularly until they sprout. Don't let the soil dry out.
- Bush beans can be planted in rows 2.5 to 3 feet apart, with seeds placed 1 to 2 inches apart. After the plants germinate, thin the seedlings to 3 to 4 inches apart.
- Pole beans need some type of support on which to grow. The support should be 6 to 8 feet tall. Be sure the trellis, teepee, fence, or other support is in place before you seed. Plant 3 to 4 bean seeds per pole, spaced at least 2 to 3 inches apart. Space poles, trellises, or teepees 3 to 4 feet apart.
Bush beans begin producing before pole beans. Most bush beans are determinate, meaning that the majority of the harvest appears within a very short period, usually 2 to 3 weeks. Succession planting every two weeks will keep your bush bean harvest going longer.
Green Bean Plant Care
Beans need full sun for the best yield. Beans tend to stop flowering in the extreme heat of summer, but keep them well-watered, and they will resume flowering and production when temperatures cool. Full sun also helps keep the plants dry and less likely to be affected by a disease.
Beans like moderately rich soil with a slightly acidic pH. You can amend the soil with organic matter. Remove weeds prior to planting to prevent competition for water and nutrients. As the bean grow, weed carefully around the plants, as their shallow roots can be easily damaged.
Green beans need 1 inch of water per week. Use a drip irrigation system for supplemental watering to avoid splashing soil onto the leaves, which can lead to soil-borne disease. To determine if the plants need water, stick your index finger about 1 inch into the soil near the base of the plant. If the soil is dry, it's time to water. Plants that are under-watered will stop flowering. Beans have shallow roots, and mulching helps to keep them cool and preserve moisture in the soil.
Temperature and Humidity
Green beans germinate best when soil temperature is between 70 and 80 degrees Fahrenheit. If the soil temperature is below 60 degrees, seed will germinate more slowly and are susceptible to rot. The plants grow best when the air temperature is between 65 and 85 degrees. Green beans grow in all humidity conditions if properly watered.
Because they are legumes, beans fix nitrogen in the soil, so avoid a high-nitrogen fertilizer. Instead, use a 10-20-10 fertilizer to feed the plants throughout the growing season, following the product directions. Pole beans produce over such a long period that they benefit from a feeding or a side dressing of compost about halfway through their growing season.
Are Green Bean Plants Toxic?
Many bean types are not intended to be eaten raw, and some are technically toxic when eaten uncooked or undercooked. Red kidney beans are perhaps the most common toxic bean. Eating just a few raw or undercooked kidney beans causes diarrhea and vomiting.
Green Bean Varieties
- 'Kentucky Wonder': An old pole variety of string bean that's highly popular and tastes great
- 'Bountiful': An early producing, stringless heirloom bush bean
- 'Golden Wax Bean': Easy producing, soft-textured, yellow bush bean
- 'Royal Burgundy': Purple pods that turn green when cooked; early-producing bush bean; resistant to the bean beetle
- 'Lazy Housewife': German heirloom pole bean, so named because it doesn’t require stringing
- 'Triomphe de Farcy': A readily available French haricot vert heirloom bush bean
- 'Romano': Classic broad, Italian-style green bean with meaty flavor; bush or pole
Harvesting green beans is an ongoing task, and the more you pick, the more beans the plants will set. You can start to harvest anytime after the beans form. Gardeners usually harvest the beans when they are young and tender--about the size of a small pencil. Overly mature beans can be tough and stringy.
In general, bush beans are ready to pick in 50 to 55 days after planting. Pole beans will take 55 to 65 days, depending on the variety. Check the packet to be sure your choice will have time to mature in your growing season. Harvest by gently pulling each bean from the vine or by snapping them off at the vine end. Be careful not to damage the plant when harvesting.
Pole beans need time to allow their vines to grow before they start setting beans. They begin producing later than bush beans but continue to produce throughout the growing season. Keep harvesting the beans, or the seed pods will mature, indicating to the plant that it should stop flowering and setting beans.
Common Pests and Diseases
Lots of insects and animals love beans as much as you do, including:
- Mexican bean beetles: These pests will eat the flowers, the beans, and especially the leaves.
- Spider mites: These tiny pests pierce the leaf surface and suck the sap, often causing leaves to die.
- Japanese beetles and aphids may also attack bean plants.
- Bean leaf beetles can girdle the stems near the soil line and chew holes in the plant's leaves.
- Deer and groundhogs will eat entire bean plants, and fencing is necessary to stop them.
Fungal diseases, such as Alternaria leaf spot, can be a problem in damp conditions. Other diseases, like Anthracnose, bacterial blight, white mold, bean rust, and mosaic virus can also affect bean plants. Help prevent diseases by keeping the vines dry; don't overcrowd the plants, and provide plenty of good air circulation. You can also look for plant varieties that are bred for disease-resistance.
Li, Yu Pin, You, Ming Pei, Colmer, Timothy D., Barbetti, Martin J. Effect of Timing and Duration of Soil Saturation on Soilborne Pythium Diseases of Common Bean (Phaseolus vulgaris). Plant Disease, 99,1, 2015, doi:10.1094/PDIS-09-13-0964-RE
Phaseolus Vulgaris. North Carolina State University Cooperative Extension.
Degu, Tizazu, Yaregal, Wasihun, Gudisa, Tesfaye. Status of Common Bean (Phaseolus vulgaris L.) Diseases in Metekel Zone, North West Ethiopia. Journal of Plant Pathology and Microbiology, 11,5,494,2020, doi:10.35248/2157-74126.96.36.1994