Staple and comfort food icon, the bean has played an essential role in the survival of people and animals since ancient times. Archaeologists have unearthed evidence that old-world legumes (lentils, peas, broad beans, chick peas, and soybeans) were used as food for more than 10,000 years in eastern Asia. Caches of lentils have been found in Egyptian tombs, signifying the reverence paid to this plant. In “History of Legumes: Man’s Use of Legumes” (www.healthguidance.org), Jason Ladock writes that “Legumes are second only to the cereal grasses as sources of human food and animal forage.”
Why are legumes so popular? Legumes, members of the bean or Fabaceae plant family, have many significant attributes. Beans are high in iron, potassium and magnesium, and are also an important source of protein and fiber. They are easy to grow, and, when dry, can be stored for long periods of time without losing viability if they are kept in a cool, dry, dark environment. Beside their nutritive benefits, the USDA Soil Quality Institute reports that beans have an ability to fix atmospheric nitrogen with the help of symbiotic Rhizobia bacteria living in their roots.
An inclusive term, “beans” commonly refers to large-seeded plants that include peas, soybeans, peanuts, and vetches. Beans are generally a summer crop that needs warm weather to grow (as opposed to the growing conditions of the group of plants we call peas). Other than growing temperatures, beans and peas are very similar.
Growing Beans: Bean Types
Green Beans (fresh)
Known as snap beans / string beans / runner beans / squeaky beans / French beans / stringless pod / filet beans / yellow wax beans / Romano beans / Italian snap beans (Phaseolus vulgaris).
Available in bush or pole forms with round or flat pods, these are used as an edible pod or shelling bean. Grow the pole types where space is limited. Cornell University reports that these will yield two to three times as much as the bush types in the same space. Some green beans have purple or yellow pods and often are quite decorative with swirls of color. They are very easy to grow.
Fresh green beans are not native to North America. They have been cultivated for more than 7,000 years and originated in the Andes Mountains of Peru and the Lerma-Santiago River basin of Jalisco in west-central Mexico.
Green Beans (dry)
Known as common beans / shell beans / kidney beans / navy beans / soldier beans / pinto beans (Phaseolus vulgaris). Used predominantly as soup beans. Harvested dry.
Lima Beans (Phaseolus lunatus)
Both bush and pole varieties exist. Available as white, black, red, orange, and mottled seeds.
Small-Seeded Lima Beans
Known as butter beans / Dixie beans / Henderson beans / baby lima beans (Phaseolus lunatus — Sieva type). Bush or climbing varieties. Warm temperature crop. Seeds often eaten fresh. Grown similar to lima beans.
Known as Pawi / Pavi / Tepari / Escomite / Yori Mui / Yori Muni (Phaseolus acutifolius). A drought-resistant bean native to southwest United States and Mexico.
Known as scarlet runner beans (Phaseolus coccineus). A vining plant that is great to use in edible landscaping situations. Decorative red or white flowers with white or multicolored seeds. Pods are edible when young. Seeds used fresh or dried.
Known as fava beans / horse beans / English beans / European beans / Windsor beans (Vicia faba). Best if grown during a long, cool growing season.
Known as Southern cowpeas / Crowder peas / blackeyed peas (Vigna unguiculata). Available as vining, semi-vining, and bush types. Best grown in warm, humid weather. Grow like lima beans.
Known as asparagus beans / Bora / long-podded cowpeas / Chinese long beans / snake beans, (Vigna unguiculata subsp. sesquipedalis). A type of cowpea that is eaten as immature pods like snap beans. A vigorous climbing vine for warm climates. Harvest 65 to 80 days after planting.
Edible Soybeans/Edamame (Glycine max)
Grown similar to lima beans. Requires 90 days to harvest.
Known as Indian bean / Egyptian bean (Lablab purpureus). A vining plant to 20 feet with purple flowers and vibrant electric-purple seed pods. Great to use in edible landscaping. Fast growing, and flowers attract butterflies and hummingbirds. Has edible leaves, flowers, pods, and seeds.
Known as garbanzo beans / chestnut beans / Egyptian beans / grams (Cicer arietinum). Technically not a pea or a bean. They need a long, warm growing season of about 100 days.
Known as asparagus peas / goa beans / four-angled beans / winged beans / princess beans (Psophocarpus tetragonolobus). A vining plant with almost all parts being edible. Mature pods are six to nine inches long with a high protein content.
Growing Beans: Planting Times
Beans are sensitive to cold temperatures and frost and should be planted around the average last frost date in the spring. The exact date depends a lot upon the condition of the soil — it must have warmed to 60°F and started to dry out. Seeds should be planted about one inch deep. Plant bush beans about two to three inches apart in rows two feet wide. Pole beans can be planted four to six inches apart in rows three feet wide. Alternatively, four to six seeds can be planted in hills centered about 30 inches apart. Plan to plant successive crops every two to four weeks for an extended harvest season (usually until late July in northern areas). Inoculating the seed with rhizobium bacteria may increase yields if you have alkaline soils (Colorado State University Extension reports that acid soils are a challenge for rhizobium bacteria) and use the correct bacteria for the legume type. The rhizobium bacteria have a symbiotic relationship with legumes. The bacteria invade the plant root hairs and multiply while the plant produces a protective nodule enclosure and energy for the bacteria. Payback in this mutually beneficial situation occurs when the bacteria convert nitrogen gas to ammonia in the nodules. To check on the effectiveness and quantity of rhizobium bacteria in your soil, excavate some bean roots. Upon slicing open a nodule, those that are actively fixing nitrogen will be pink to reddish, rather than tan (ineffective) or green (dying). Also be sure to check the expiration date on the inoculant package before applying, as the living rhizobia have a finite shelf life.
Contrary to popular wisdom, do not soak seeds — beans tend to germinate poorly if they absorb too much water and crack. This also applies to planting seeds in overly wet soil conditions. Instead, water after planting or plant before a heavy rain.
Beans do not like to be transplanted and are therefore best direct-seeded into the garden. But if done carefully, they can be successfully started indoors in peat, newspaper, or soil pots and transplanted into the garden. Gardeners with short growing seasons, cold and wet soil, rotting issues, or early insect pressure may want to start seeds indoors three weeks early to overcome these situations.
WHERE TO PLANT
The best sites have full sun (partial shade is tolerated but will reduce the yield), well-drained soil (but consistently moist), average fertility (too rich of a soil will produce an excess of foliage at the expense of beans), slightly acidic soil pH (6 to 6.8), and good air circulation.
If bean diseases have been a problem in previous years, do not replant in the same location, since overwintered bacterial and fungus diseases can strike again.
Watch that close cultivation or hoeing doesn’t damage the shallow, brittle, weak bean roots. Fertilize sparingly and avoid using nitrogen to promote lush growth. Extend the harvest by succession planting several sowings.
Plants under heat or water stress are more prone to becoming stringy. Mulching after the plants are about 6 inches tall will help conserve soil moisture.
Hot, dry, stressful weather conditions can cause bean blossoms to fall and fail to produce pods. Water regularly if no natural irrigation occurs. Beans need about one inch of moisture every week (especially when flowering and developing pods). To minimize disease problems, avoid wetting the foliage for prolonged periods. Water early in the day for the fastest drying time.
Consider using bush beans as cover crops.
HOW TO HARVEST & STORE BEANS
Edible Pod Peas for Fresh Eating
The best time to pick the various snap beans is when they are still young and aren’t tough and stringy (July to frost).
Since beans ripen at different times on the same bush, it is best to check them daily. Picking the beans frequently encourages more to form. Skipping a day may send some pods into the inedible category and slow down production since the plant thinks it has accomplished its goal of producing seed.
Most beans should snap nicely from the plant. Select beans that are firm, pencil thickness (or less), tender, and medium green. Harvest only when bean plants are dry to avoid bacterial blight, a serious bean disease. Cut off the tougher stem and tip end and they are ready for cooking (or eating fresh). Store pods unwashed in a tight container in the refrigerator, then wash and use as soon as possible. After several days beans may get wilty or tough. If they can’t be used fresh within three or four days, the pods can be blanched and frozen, canned, or pickled.
Dry Beans for Longer Storage
Shell beans can be harvested at three different stages. They can be harvested young in the pod before the seeds are visible from the outside (bump free) and eaten like snap beans. They can also be harvested when a little more mature (but still green), when the beans inside have formed significantly but before the pod is dried. These tender beans (shell outs) are separated from their shell and cooked. The more common way to harvest shell beans is to leave the pods on the plant until they are hard and dry (but before the pods split and drop the seed). The dry beans can be shelled by hand or threshed by beating the pods until they break and release the beans. Another method is to uproot the bean plants and hang them upside down inside a large garbage bin while beating them against the sides. The seeds, once removed from the pod, can be stored in a cool, dry place for months.
If snap beans are not harvested at the young, tender stage, they can be left on the plant to form shell outs or even left on to use as dry beans.
Growing Beans: Preventing Bean Pests & Diseases
Mexican Bean Beetle & Bean Leaf Beetle
Look for clusters of yellow eggs hanging vertically from the underside of the snap or lima bean leaves (they also like soybeans and other types, too) in early summer. Soon fuzzy, bright yellow insects will appear and start feeding on bean leaves — these are the Mexican bean beetle larvae, which are very destructive as they skeletonize the leaves. The adult does less damage and looks like a yellow-orange ladybug with eight black spots in rows on each wing. The adult is a good flyer and can travel far to find new bean fields. The beetles overwinter in moist, protected debris. Control measures include cultivating to destroy overwintering locations; handpicking eggs, larvae or adults; using floating row covers; planting a heavy bean crop in the spring (beetle populations are heaviest later in the summer); using a trap crop; using predators; spraying with azadirachtin, garlic, cedar oil, or mineral oil; and planting less-preferred types like mung beans, cowpea, and soybeans. This is one of the top insect pests in many areas.
Leafhopper feeding shows up as a browning (called hopperburn) and curling of the leaves with the greatest damage on young plants. Most of this damage is the plant responding to saliva from the sideways-walking, wedge-shaped insect, which is long gone by the time damage shows. The leafhopper is a major dry bean pest in many areas of the country and can have four to six generations during the summer. Control includes floating row covers, not planting beans near alfalfa fields, and successive plantings.
Cutworms & Army Worms
The Western bean cutworm is marching eastward and is causing significant injury on dry beans as the larvae chew holes in the pod walls and developing seeds. Most feeding occurs on cloudy days or at night. Controls for the cutworm and armyworms include plowing to reduce overwintering larvae, encouraging bird and skunk feeding, and using Bt on larvae.
Several bacteria attack beans, and for many the early symptoms may look like anthracnose (a fungus). Later symptoms include enlarging, irregular brown patches with yellow edges on the leaves. Many bacterial diseases are seedborne and can overwinter in bean debris and spread fast and far via the rain. Humid and moist conditions favor the spread of these diseases. Control includes using certified seed, planting on a rotation (avoid replanting beans in the same place for three years), avoiding harvesting or working the bean fields with leaves that are wet, plowing down bean stubble, planting resistant varieties (if available), and spraying with copper (check the label for recommendations).
Root Rot, Seed Rot, & Damping Off
Root rots, damping off, and seed rots are all destructive at the time just before seedlings emerge and are caused mostly by fungi present in the soil. Significant losses may occur, especially if cool, wet weather just after seeding is followed by hot, dry weather.
Controls include crop rotation (don’t grow beans in the same location for four to five years if these diseases are a problem), improving drainage and breaking up hard pans, hydrogen peroxide or dioxide spray or soil drench, and delaying planting until the soil is over 65°F.
By Anne Van Nest. This article appeared in the February 2013 issue of Acres U.S.A.