Lima beans (Phaseolus lunatus) are a warm-season legume grown for their broad, flat pods and pale green seeds, eaten fresh as a "shelling" bean or left to dry for storage. Gardeners also know them as butter beans, for the smooth, buttery texture they take on when cooked. They are not difficult to grow once the soil is properly warm, which makes them a reasonable next step for anyone who has already grown snap beans, though the long season they need rules them out in short-summer gardens.
Sowing and planting
Lima beans need warm soil to germinate well — in cold, wet soil the seed is more likely to rot than sprout. Wait until the soil has warmed thoroughly and all danger of frost has passed before sowing. In zone 6b, that usually means late spring, once nighttime temperatures are reliably staying in the 60s°F (above about 16°C). Sow seed directly where it is to grow rather than starting it indoors, since lima bean roots dislike disturbance and the seedlings rarely transplant well.
Plant seed about 1 inch (2.5 cm) deep and roughly 6 inches (15 cm) apart, in rows spaced 24–36 inches (60–90 cm) apart to leave room for bush types to spread or for a trellis to go in alongside pole types. If your soil tends to stay cool and damp in spring, warm it ahead of time under black plastic or row cover for a week or two, and consider soaking seed overnight in water to speed germination along. Bush varieties mature faster and suit a shorter or cooler season better; pole varieties need more warmth and time but keep cropping over a longer stretch.
Growing on
Keep the soil evenly moist through germination and early leaf growth, then watch it more closely once flowering begins. Lima beans are prone to dropping flowers and small pods during a dry spell, so steady watering through bloom and pod fill matters more here than at any other stage. Water the soil rather than the foliage where you can, since wet leaves invite fungal problems.
Feed lightly. Like other legumes, lima beans fix some of their own nitrogen from the air with the help of soil bacteria, so heavy nitrogen feeding tends to produce lush leaves at the expense of pods. Working a balanced, general-purpose fertilizer into the soil before sowing is usually enough; side-dress sparingly (working a little extra fertilizer into the soil alongside the row) only if growth looks pale or has stalled.
Bush types are self-supporting and need no staking, though a short stake or twiggy branch pushed in nearby can stop a heavily laden plant from flopping onto the soil. Pole types climb 6–10 feet (1.8–3 m) and need a sturdy trellis, a tepee of canes, or a fence ready at sowing time, since the vines climb fast once they get going. Neither type needs pruning; with pole beans, just guide the young vines onto their support as they start to climb.
Harvesting
Pick lima beans for fresh shelling once the pods feel full and firm but are still bright green — the beans inside should be plump, not hard or starchy-dry. Pick by hand, holding the vine steady so the stem doesn't tear, and shell the beans promptly, since fresh-picked lima beans don't keep well for long. Picking regularly, rather than letting pods sit, encourages the plant to keep setting new ones.
For dried beans, leave the pods on the plant until they turn brown and papery and the beans rattle inside when shaken. Pull whole plants or strip the pods by hand, then finish drying indoors somewhere warm and airy for a week or two before shelling. Store fully dried beans in an airtight container out of direct light, where they typically keep well for months.
Problems and pests
Seeds fail to come up
Usually cold, wet soil, which causes the seed to rot before it has a chance to sprout. Wait for the soil to warm fully before sowing, and avoid overwatering a freshly sown bed.
Flowers or small pods drop off
Often brought on by a dry spell or a stretch of very hot weather during flowering. Keep watering consistent through bloom and early pod set, and mulch to help the soil hold moisture.
Leaves show a powdery white coating
This is powdery mildew, a fungal disease that coats leaves in a white, dust-like film, usually worse in humid weather with poor air circulation. Space plants properly, water the soil rather than the leaves, and remove badly affected foliage.
Leaves show holes or ragged chewed edges
Likely bean leaf beetles or similar chewing insects feeding on the foliage. Handpick beetles where practical, clear away plant debris where they can overwinter, and cover young plants with row cover while they're small and most vulnerable.
Leaves are yellow, mottled, and growth is stunted
Can point to a virus, such as a bean mosaic virus, usually spread by aphids. There's no cure once a plant is infected, so remove and discard affected plants and control aphids to limit further spread.
Varieties worth growing
- Fordhook 242 – a reliable bush variety bred for heat tolerance, with heavy yields of large, plump beans.
- Henderson's Bush – a smaller-seeded heirloom bush type valued for its mild, buttery flavor and earlier maturity.
- King of the Garden – a vigorous heirloom pole variety with large, flat pods; needs a tall, sturdy trellis.
- Christmas Lima – a pole heirloom with large, maroon-and-white speckled seeds and a rich, nutty flavor when dried.
- Jackson Wonder – a speckled bush heirloom known for tolerating cooler soil better than most lima beans.