Lima bean looks and behaves like a cousin of common bean, but the two are different species and won't cross -- lima's own crossing risk comes only from other lima bean varieties, and it outcrosses somewhat more readily than common bean due to more insect-visited flowers.
New to terms like isolation distance or outcrossing? See the Seed-Saving Glossary.
Seed-Saving Difficulty
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Moderate Difficulty
Low to moderate crossing risk.
How It's Pollinated
Mostly self-pollinating, with more insect-carried outcrossing than common bean
(Low to moderate crossing risk)
Scientific name: Phaseolus lunatus
Domestic Crops It Can Cross With
- Other lima bean varieties, more so than common bean since flowers attract more insect visits
- Does not cross with common bean (Phaseolus vulgaris) -- different species despite the shared genus
Wild Relatives & Feral Species
- Wild Phaseolus lunatus exists in Central and South America but is not a practical concern outside that range
Separation Distances Required
Minimum: 20-30m between varieties
Recommended: 50m for extra security
Strict: Bag flower clusters for guaranteed purity
Seed-Saving Strategies
- Allow pods to dry fully and turn brown/tan on the plant
- Shell once pods are crisp and papery
- Finish drying seed fully before storing
- Store dry -- viable 3-4 years