Beans and peas are among the easiest seeds to save—just leave them on the vines until they are dry, and harvest when they are at the same stage as you wood for harvesting dry beans for eating. Since isolation distances for members of the same species can be greater than what is possible in an urban setting, gardeners should plant just one variety of a species. Since there are quite a few species, one can still grow a great variety in a single season. Below are some descriptions of legume species, along with isolation distances required if more than one variety of the same species is grown.
Common Bean (Phaseolus vulgaris)
Isolation distance: 20 feet
Most beans sold commercially and grown for “green bean” (even if they are green, yellow, or purple) are members of the Phaseolus vulgaris species. Most in this species can be eaten as “green bean,” fresh shelled, or dry. This species includes pole and bush type.
Runner Bean (Phaseolus coccineus)
Isolation distance: 50 feet
Most have beautiful red flowers that attract humming birds and butterflies. Since they are a species different from the common “green bean” (see above), a few of these runners can be grown amongst your usual beans, and you can still save seed from them all.
Cowpea/Longbean (Vigna unguiculata)
Isolation distance: 50 feet
This species includes cowpeas, black-eyed peas, Southern peas, and Asian long beans or yard-long beans. These can be harvested fresh or dry.
Fava Bean (Vicia faba)
Isolation distance: 50 feet
Unlike most beans, these are extremely cold tolerant and can be planted out very early in the spring, as for peas. Harvest when green for fresh shelled, remove outer shell, boil, and then remove seed coats.
Adzuki Bean (Vigna angularis)
Isolation distance: 50 feet
Chickpea (Cicer arietinum)
Isolation distance: 20 feet
Lentil (Lens culinaris)
Isolation distance: 20 feet
Pea (Pisum sativum)
Isolation distance: 20 feet
This species includes edible pod and shelling peas, usually eaten fresh but most can be left for dry culinary use as well. Unlike most beans, these prefer cool weather and are sowed in early spring.
Soybean/Edamame (Glycine max)
Isolation distance: 20 feet
Harvest green for edamame or let mature for dry storage.
Tepary Bean (Phaseolus acutifolius)
Isolation distance: 20 feet
Lima Bean (Phaseolus lunatus)
Isolation distance: 50 feet
These aren’t just the white ones! There are loads of beautiful colorful and flavorful limas out there.
