Lima bean, scientific name Phaseolus lunatus, is a legume known to be a good source of dietary fiber and a fat-free source of high quality protein. As a tender annual plant native to Central America it is no surprise that these plants are warm season crops. They require a temperature of 65°F (18°C) to germinate.
There are two main types of Lima bean: Bushy (also called butter beans), have smaller seeds and reach about 2 feet (60 cm) in height; and vine & Pole Lima beans, these have larger seeds and reach 10 to 12 feet (3 to 3.5 m) in height.
lima bean pods photograph by University of Delaware Carvel REC (CC: https://www.flickr.com/photos/carvel/)
Ideally four to seven plants should be grown per family member.
It is the beans not the pods that are eaten. They contain soluble fiber that helps lowers cholesterol and regulates blood sugar levels; and insoluble fiber for the prevention of digestive disorders, constipation, diverticulitis, and irritable bowel syndrome.
Lima beans or butter beans prevent blood sugar levels from rising too rapidly due to the presence of huge amount of absorption-slowing compounds in the beans. The soluble fiber content absorbs water in the stomach, forming a gel-like substance that slows down the beans’ carbohydrates metabolism.
Lima beans are flat, crescent-oval-shaped seeds that are tender annuals. There are two variants of lima beans: the bush and vine or pole type. The bush beans tend to have smaller seeds and can only grow around two feet (60 cm) high but bear beans more quickly than the pole lima bean type. The pole lima beans can grow 10 to 12 feet (3 – 3.5 m) tall and produces larger seeds.
The bush types –which are the small-seeded limas—are also called sieve beans, butter beans, Carolina beans, Madagascar beans, Burma beans and baby limas.
The pole lima beans are also called potato limas due to their shape and size, and are often sold as dry beans.
Depending on the variety, Lima beans have pale green pods that can range from three to eight inches (7 – 20 cm) long. The plant’s leaves are comprise three leaflets and will continue to produce white flowers until the forst so long as old pods are removed before beans fully mature.
Lima bean plant with traces of tan spot by Scot Nelson (CC: https://www.flickr.com/photos/scotnelson/)
The bush lima bean variety can be harvested from 60 to 80 days from sowing, while the pole bean variety is ready for harvest in 80 to 95 days.
It is vital to have a well-chosen site that has full sunlight. Sow the seeds a few weeks after the last frost and when the temperature of the soil has been at least 65°F (18°C) for week to encourage quick germination. The plant should be grown in full sun, when they grow in partial shade the harvest will not be a full yield. The soil should have a pH of 6.0 to 6.8 and be loose, well-drained, and rich in organic matter. Work in a lot of aged compost when preparing the planting beds in advance.
Avoid planting the beans on soil that is rich in nitrogen or where green manure crops have just grown, as these conditions will produce green foliage with fewer beans.
Sow lima beans one and a half inches to two inches (3 – 5 cm) deep.
Bush lima beans variant should be planted three to six inches (7 – 15 cm) apart with rows from 24 to 30 inches (60 – 75 cm) apart. Pole lima beans should be planted six to ten inches (15 – 20 cm) apart with rows 30 to 36 inches (90 – 100 cm) apart.
At planting, set stakes, poles, or supports in place. Pole beans can also be planted in upturned hills, five or six seeds per hill with hill spaces 40 inches (100 cm) apart.
Weaker seedlings should be removed by cutting them off at soil level using scissors, being careful not to disturb the roots of the other seedlings. Beans can be crowded as they will use each other for support.
Start beans indoors as early as two or three weeks before the last frost in spring and transplant them into the garden three or four weeks after the last frost.
Lima beans can be initially grown in a peat pot or in bio-degradable paper and then set into the garden to avoid disturbing the roots of the plant.
Follow bush lima beans with pole lima beans, or sow a succession of bush lima beans every two weeks to allow a continuous harvest through the growing season. Beans can continue growing in the garden until the first frost of fall.
The long-maturing pole lima beans require a longer growing time and it is not advised to grow them in areas with short seasons. This annual plant will not set pods in wet or cold weather or in temperatures above 80°F (27°C). Thus, it is vital to time their planting season wisely to avoid hot weather.
In areas with a mild-winter, the plants can also be sown in the autumn for a winter harvest.
Lima beans should be grown in soil that is well drained and evenly moist. Beans that are planted in wet soil may germinate poorly and crack. Avoid soaking seeds in advance of planting or over-watering after sowing. It is important that the soil is kept moist, especially during pod and flower formation.
Mulch once the soil temperature is greater than 60°F (15°C) as this will help to conserve moisture. Use aged garden compost and avoid using nitrogen-rich fertilizers or green manures.
For companion planting, the bush lima bean can be planted with celery, cucumbers, Maize, summer savory, and potatoes. Pole lima beans can be planted with scarlet runner beans, corn, sunflowers and summer savory. Avoid planting the beans with beets, Kohlrabi, and onions.
Beans can be infested by pests, often being attacked by flea beetles, bean beetles, aphids, mites, and leafhoppers. A blast of water from the hose can spray away aphids, mites, and leafhoppers. Aphids can spread bean mosaic virus so it is best to get rid of them as soon as possible, furthermore, it is best to use mosaic resistant varieties. Look out for infestations and eggs and crush them between your fingers and thumb.
Diseases include seed and root rot, and bacterial blight (best prevented by using disease free commercial seed). Always keep the garden clean and free of debris in order to avoid pests from harboring the vegetable patch. Due to beans being highly susceptible to anthracnose, blight and mosaic, avoid handling plants when wet to prevent fungal spores from spreading. Remove diseased plants and properly throw them away.
Other problems include using too much nitrogen (stringy plants, low yields), and dropped blossons (dry winds, excessive temperatures).
Typically a 10 feet (3 m) row will yield about 5 to 6 lbs. ( 2 to 2.5 kg) of lima beans. Harvest when young for the best taste as they can become tough skinned.
Bush lima beans are ready for harvest season in about 60 to 80 days after sowing, while pole beans can be harvested 85 to 90 days after sowing. Harvest lima beans when pods are already plump and firm. The seeds will be full sized but not mature, the pod should be bright green, and feel spongy to the touch.
Continue picking pods continuously once they become plump to prolong flowering and allow the production of new pods. The plants will die as soon as seeds have been allowed to mature in pods.
Lima beans can be stored unshelled at 32°F (0°C) for up to two weeks in 90% humidity. They can also be shelled for canning or freezing.