Butter beans, botanically known as Phaseolus lunatus, are a warm-season legume prized for their buttery texture and rich, creamy flavor. These beans are often referred to as Lima beans, and successfully growing them at home requires understanding their specific needs for warmth and space. This guide provides practical steps for home gardeners to cultivate a successful crop, beginning with site preparation and concluding with the harvest and storage of your bounty.
Preparing the Planting Site
Butter beans are sensitive to cold and require a location that receives full sunlight, ideally six to eight hours of direct sun daily. The chosen site should have well-draining, loose soil to prevent the large seeds from rotting before germination. A slightly acidic to neutral pH range, specifically between 6.0 and 6.8, supports optimal plant development.
Before planting, incorporate organic matter like aged compost or manure into the soil to improve structure and fertility. Avoid fertilizers high in nitrogen, as beans are legumes and fix their own nitrogen once established. Excessive nitrogen encourages lush foliage growth at the expense of pod production. Planting should only occur when the soil consistently reaches at least 60°F (15°C) to 65°F (18°C).
Sowing the Seeds
Direct sowing is strongly recommended as butter beans do not transplant well due to their shallow root system. Wait until all danger of spring frost has passed and the warm soil temperature threshold has been met. While some gardeners soak seeds, Lima beans are prone to splitting or rotting if soaked too long, so plant the seeds directly into moist soil.
Plant the seeds about one to two inches deep, pressing the soil gently over them and watering thoroughly. Spacing depends on the variety chosen; bush types are compact and should be spaced four to six inches apart in rows 18 to 24 inches apart. Pole varieties, which grow vertically, require a support system like a trellis or pole to be in place before planting.
For climbing beans, sow the seeds about two to six inches apart near the base of the support structure. Pole varieties offer an extended harvest period compared to the concentrated yield of bush varieties. Maintain consistent moisture until the seedlings emerge, which typically takes seven to fourteen days depending on the warmth of the soil.
Caring for Growing Butter Beans
Once established, consistent moisture is necessary, particularly during flowering and pod-setting stages. Aim to provide the plants with about one to two inches of water per week, ensuring the water soaks deeply into the soil to promote a robust root system. Always water at the base of the plant and avoid wetting the foliage, as this encourages fungal diseases like powdery mildew.
Weed control is important during the early growth phase, as weeds compete with the shallow-rooted beans for water and nutrients. Cultivate the area very shallowly to avoid damaging the roots, or apply a layer of organic mulch to suppress weeds and help retain soil moisture. Pole varieties must be trained onto their supports early, and their extended production window means they may benefit from a mid-season side-dressing of compost or a low-nitrogen fertilizer.
Monitor the plants regularly for common pests such as aphids or Mexican bean beetles. Address any infestations with an appropriate horticultural soap or organic control method. Avoid working around the plants when the foliage is wet, as physical contact can easily spread bacterial or fungal diseases. Proper airflow, especially in humid conditions, helps to mitigate disease risk.
Harvesting and Curing
Butter beans can be harvested as green shelling beans or as dried beans for long-term storage. For fresh shelling, pick the pods when they are plump, firm, and bright green, indicating the beans inside are fully mature but still tender. This stage ensures the best texture and flavor for immediate consumption.
To harvest dried beans, allow the pods to remain on the plant until they turn brown, become brittle, and the beans inside rattle. Shell the beans and spread them in a single layer indoors to cure for several weeks, ensuring they are completely moisture-free. To prevent insect infestation during storage, shelled dry beans can be sterilized by freezing them at 0°F for 48 hours or baking them at 160°F for 30 minutes. Store the fully dry, sterilized beans in an airtight container in a cool, dark location.