Growing beans in home gardens
A quick guide to beans
- Edible beans include snap beans, shelling beans or dry beans.
- Bean plant growth habits include pole beans, bush beans and half-runners.
- Bean plants do not need as much fertilizer as other crops.
- Plant seeds directly in the garden once the soil has warmed.
- Install pole bean supports at planting time.
- Pick snap beans before the individual seeds inside the pods bulge.
- Pick shelling beans when the pods are thin and tough, but not dry.
- Pick dry beans when the pods are dry and the beans inside rattle.
Beans for different uses
The common bean (Phaseolus vulgaris), is a popular garden vegetable in Minnesota, grown for snap beans, shell beans or dry beans. Some varieties are suited for all three uses.
Pods of all types may be green, yellow ("wax"), purple or striped. Purple coloring disappears during cooking. Cooked purple beans will appear dark green.
Soil pH and fertility
Beans grow best in slightly acidic to neutral soil, pH between 6 and 7.
Clay or silt loams are better for bean production than sandy soils, although good drainage is important.
Use well-rotted manure or compost at planting to increase soil organic matter.
Do not use any fertilizer containing a weed killer (“Weed and Feed”), as it may kill your vegetable plants.
Many soils in Minnesota have populations of the bacteria Rhizobium. This bacterium forms a beneficial relationship with beans. This relationship helps plant growth and bean yield.
To encourage these benefits, you can purchase powdered Rhizobium inoculum and treat the seeds before planting. Add a little of the powder to the seed packet and shake it up. Be sure to purchase inoculum suitable for beans, and not specifically for peas.
Snap beans, also called "green beans" or "string beans," are ready for harvest when the pods contain immature seeds, and the pods are still succulent. You can cook or pickle snap beans, as well as eat them raw.
Shelling beans, sometimes called "horticultural beans," are ready for harvest when the pods have begun to dry and become more fibrous, and the seeds are fully sized but still soft. “Shell out,” or remove the seeds from the pods, and use them as a vegetable side dish or in soups.
Dry beans are ready for harvest when the pods and seeds have completely dried. Dry beans keep indefinitely and have many uses. They are a high-protein, high-fiber food.
Although dry beans are inexpensive and widely available in grocery stores, gardeners often find that their homegrown crops are cleaner and cook faster.
The selection of dry beans available through seed catalogs is much greater than the selection of dry beans in grocery stores, with hundreds of different sizes, colors, markings and uses.
Most beans are non-hybrids and all are self-fertile so you can also save dried seed for future planting.
Pole beans are twining vines growing up to six feet and sometimes taller that you must support with a trellis or similar structure. Pole beans flower and produce new pods all through the season.
You can harvest pole beans many times during the summer, with enough beans gathered for that day’s meal. Pole beans are well suited to smaller gardens, taking up less ground than would be necessary to get similar production from bush beans.
Another advantage in growing pole beans is that when the weather is extremely hot during flowering, bean plants may not set fruit. Pole beans will fail to set only a few pods, and then continue producing more once the weather returns to normal.
Bush beans are upright plants that do not need support, growing about two feet tall. They have a shorter period of flowering and pod set, although they may continue to flower and produce pods as long as you regularly harvest them. Bush beans are good for canning and freezing, since you can gather a large harvest of beans at one time from a row of plants.
You may lose a large portion of the crop because the plant produces all of its flowers during a short span of time.
Half-runner vines can benefit from some support, although they usually do not grow to more than three feet tall.
You can grow several other bean species in Minnesota gardens.
Scarlet runner beans
Scarlet runner beans (Phaseolus coccineus) produce long vines, up to ten feet, and require a trellis. Their abundant red, pink, or bicolor blooms are attractive to hummingbirds and as an ornamental.
The pods have a rich, delicious flavor, and you should pick them when they are short, between four and six inches. Use them like you would with snap beans. Once the pods become too tough for snap bean use, you can shell out the immature seed, or allow it to mature and dry. You can cook dried runner bean seed like dried common bean seed.
You can grow soybeans (Glycine max) successfully in most of Minnesota. "Vegetable soybeans" or "edamame" are varieties good for use as fresh-shelled beans.
Plants are tall, up to three feet, but sturdy and upright, requiring no support. Inoculation with Rhizobium may help plant growth and yield. Rabbits and woodchucks eat soybean plants, so you may need to install fencing to keep out these animals.
Pick the pods when plump seeds have caused them to bulge, but while they are still green. Do not eat the hairy pods. You should cook the beans in boiling water while still in the pod, and then shell them out after cooking. Home gardeners can grow black-seeded varieties, in addition to the green edamame that are available frozen in grocery stores.
Do not eat raw soybeans.
Lima beans (Phaseolus lunatus) are an old-fashioned garden treat, shelled out or allowed to mature and dry.
They require warm soils, warm weather, and a somewhat longer growing season than common beans. Some areas in Minnesota with hotter, longer summers are better for lima production than other areas. During a cooler-than-normal summer, they will perform poorly.
Many Minnesota gardeners have turned to vegetable soybeans or shelled common beans as a substitute for fresh limas, since they perform better in most parts of the state. For gardeners who love that buttery lima taste, there are a few lima bean varieties requiring less heat and a shorter season. It is worth consulting seed catalogs or seeking out a garden center with a wide seed selection to find the best varieties for your garden.
Choose either pole or bush plant habits and grow limas just as you would common beans. While the ideal soil for common beans is a well-drained clay loam, lima bean plants grow best in a coarser-textured, sandier soil.
Harvest for fresh-shelled beans when the seed color has changed from green to cream or white, and the pods are starting to bulge in the shape of the seed. For dried limas, allow the pods to dry completely, and then thresh as you would common beans.
Raw lima beans may contain small amounts of toxic glucosides. Although most modern varieties contain little or none of the toxins, cooking lima beans removes any that are present. Do not eat raw lima beans.
Yard-long beans (Vigna unguiculata), also known as "asparagus beans," are popular in Asian dishes.
You can grow them in Minnesota, although yields are likely to be low. This species requires very warm weather to produce pods, and the pods can suffer chilling injury from temperatures in the forties.
The very long vine of this plant—sometimes more than ten feet long—requires support.
Some varieties produce pods up to 18 inches, others more than two feet. Watch the developing pods, which may appear puffy or inflated while growing. They will appear tight or constricted when they are over-mature, so pick when they are long, tender, and slightly puffy-looking, before the seeds expand.
Black-eyed peas and cowpeas
Black-eyed peas and cowpeas (Vigna unguiculata) are the same species as yard-long beans, and have similar requirements for warm soils and warm air temperatures. In cooler parts of the state, the growing season may not be long enough or warm enough to mature the seed fully.
Gardeners grow these varieties for the mature dried seed. The plants usually are bush-types, rather than tall vines. One short-season variety to try is California Blackeye 46.
Fava beans (Vicia faba), unlike other beans, require conditions similar to those needed to grow peas: cool temperatures with highs only into the low eighties. In most of Minnesota, favas will set only a few pods before the weather turns too hot. In cooler areas, such as along the Lake Superior shore, fava bean growth may be successful.
Grow as you would peas, planting early in the spring. The sturdy, erect plants do not need support. The pods will first grow upright, and then begin to droop as the seed matures.
Pick the favas while green, as the seed starts to bulge a bit in the pod. Shell the beans from the pod, and then remove the white outer coating of the seed either before or after cooking. You can also use fully mature favas as dry beans.
Some people are sensitive to raw favas and can become quite ill if they eat them. Although sensitivity to the raw seed is most common among people of Mediterranean ancestry, it is impossible to predict who is sensitive. Always fully cook favas before consumption.
The hyacinth bean plant (Lablab purpureaus, Dolichos lablab) with its beautiful purple flowers, is common as an ornamental vine in Minnesota. You can also eat the green pods. Harvest as for snap beans, when the pods are juicy and tender. Always cook hyacinth bean because it will remove the toxins that the seed can contain.
- Plant beans once the soil has warmed. In much of Minnesota, this is not until late May or even early June.
- Bean seed planted in cold soil may rot rather than germinate, and plant growth will be very slow in cooler weather.
- Some gardeners plant bush beans in succession, every two weeks until early August, for production throughout the summer and into fall. Pole beans will continue to flower and bear until frost, so there is no need for succession planting.
- Plant seeds about an inch deep, or according to package directions. Plant small-seeded beans more shallowly than larger seeds.
- Install pole bean supports in place at planting time. Make a simple trellis of six-foot stakes and twine, or set up a teepee of bamboo poles or long branches. Plant seeds in a row in front of the trellis. Plant seeds four inches apart or two to four seeds at the base of each pole.
- Sow bush bean seed in single or double rows, with seeds four inches apart and rows two to three feet apart.
How to keep your bean plants healthy and productive
- Beans grown in more moisture-retentive soils may not need watering except during dry weather, but those grown in sandy soils will require watering often.
- One inch of rainfall per week is good.
- An inch of water will wet a sandy soil to a depth of ten inches, a heavy clay soil to six inches.
- Use a trowel to see how far down the soil is wet. If it is only an inch or two, keep the water running.
- Frequent, shallow cultivation will kill weeds before they become a problem.
- Bean plants form a deep taproot, but also have some lateral roots closer to the surface of the soil, so it is important not to cultivate too deeply. Be careful not to damage the plants when cultivating.
- A dense stand of bush beans will discourage weeds within the row.
- Mulching with herbicide-free grass clippings, weed-free straw, or other organic material to a depth of three to four inches can help prevent weed growth, decreasing the need for frequent cultivation.
- A number of root-rotting pathogens can infect beans. The plants begin to brown and die from the soil up, and eventually collapse.
- Practice crop rotation by rotating beans around the garden, and not planting in the same spot more than one year in four. Peas are hosts to the same diseases, so make sure to account for all legumes in planning the crop rotation.
- Viruses can be a problem in bean production. Insects spread viruses from one plant to another.
- If you notice a single plant in a row that has unusual leaf coloration or strangely puckered leaves, pull the entire plant and dispose of it.
- Many bean varieties are resistant to viruses, and selecting resistant types is the easiest way to prevent disease.
- Anthracnose, rust, several bacterial leaf spot diseases including blight, powdery mildew and downy mildew are all possible. Poor air circulation creates conditions favorable for these diseases.
- Avoid overly dense rows, control weeds and provide support for climbing beans to improve air circulation around plants.
- For assistance in diagnosing unknown problems, visit the University of Minnesota Extension diagnostic site “What’s wrong with my plant?”
You can pick snap beans at any stage of pod formation, until the shape of the individual seeds inside becomes apparent, causing the pods to bulge. After this stage, the pods are typically less juicy and more fibrous.
Snap beans will hold their quality after picking for several hours at room temperature. It is best to refrigerate them if you do not cook them immediately.
Pick beans for canning at the more mature stage, so that they remain firm after processing.
Pick filet beans when they are very slender. For other types, picking pods before they have gained more size can decrease yield.
Harvest shelling beans when the pods have become thin and tough, but not dry. The beans within will have developed their mature markings, although their color may still be pale. The pods should split open easily, and you can easily remove the beans.
Refrigerate shelling beans.
Harvest dry beans when the pods are dry and the beans inside are dry enough to rattle. Cut or pull the entire plant if the cold, rainy weather of autumn comes before the beans are fully mature. Then hang upside-down indoors to dry.
Once the pods and beans are completely dry, strip the pods from the plants and shell out by hand. For a larger crop, place the pods in a burlap sack and thresh by hitting the bag with a stick.
Winnowing is the process of removing little bits of plant material from the seed. Take the seeds outdoors on a dry, windy day and pour them from container to container, allowing the wind to blow through the stream of seeds. The wind will remove lightweight plant fiber.
Store dry beans in bags, jars, or other containers in a dark, dry place.
Preservation: food safety first
- Home-canned beans are one of the most common sources of botulism poisoning. Properly prepared pickled beans do not cause this poisoning, because they contain so much acid from vinegar.
- If you wish to put up jars of plain beans, you must follow canning instructions exactly, including the use of a pressure-canner to process the jars.
- If you do not have a pressure canner, plan to freeze the beans.
- Of all common beans, only kidney beans are toxic when raw. Both red kidney beans and white kidney beans (sometimes called "cannellini") contain toxins that cooking can remove.
Reviewed in 2018