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How to Grow Lima Beans: Bush and Pole, Sowing to Harvest

Lima beans need warmer soil than any other bean — 65 °F minimum — and a longer season. Bush types crop in 65 days, pole types in 90 but far heavier.

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Lima beans pods
Photo: landracemaizegenomics, Pixabay Content License, via Pixabay
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Lima beans are grown exactly like green beans with one change that decides everything: they need much warmer soil. Sown at the same time as runner or snap beans, a lima row frequently just rots.

Bush or pole

The choice is mostly about season length
Bush limaPole lima
Days to harvest60–7585–95
Height2 ft6–10 ft
SupportNoneRequired
YieldModerate2–3× higher
Picking window2–3 weeksWeeks, continuous
Best forShort summersLong summers

If your frost-free season is under about 110 days, grow bush types and do not be tempted by pole yields you will not have time to collect. Where the season allows, pole limas are substantially more productive per square foot of bed.

The temperature rule, and why it is strict

Lima beans are the most cold-sensitive of the common beans. Below about 60 °F the seed sits there and rots rather than germinating, and cool damp soil is exactly the condition fungi need.

Buy a soil thermometer and read at two inches deep, mid-morning. Air temperature is misleading — a warm week in April over cold soil tells you nothing.

Do not start them indoors to get ahead

It is the obvious workaround and it rarely pays. Beans have brittle, fast-growing taproots that resent disturbance, and a transplanted lima frequently sulks for two weeks — losing the time you tried to gain.

Direct sow, late, into warm soil. A row sown two weeks “late” into 68 °F soil overtakes one sown early into 58 °F soil.

Why they stop setting pods

This is the complaint that comes up every August, and it is almost always heat.

Above roughly 85 °F, and particularly with warm nights above 70 °F, lima flowers abort. The plant keeps growing, keeps flowering, and sets nothing. It is not sick and it has not finished — it resumes as soon as the weather eases, often producing a heavy late crop.

The other two causes:

  • Water stress during flowering. Keep it to about an inch a week, deeply and evenly. Alternating drought and flood is worse than consistently moderate
  • Too much nitrogen. A lush dark-green plant with no pods has usually been fed

So the response to a stalled plant is: mulch heavily, water consistently, stop feeding, and wait.

Harvesting the two different ways

For fresh shelling beans: pick when pods are plump and firm with the seed shapes clearly bulging, while the pod is still green. Once pods yellow the beans are starchier — still good, just less tender. Picking regularly keeps the plant setting more.

For dry beans: leave them alone. Let the pods go brown, papery and rattly on the plant, then pull the whole plant and hang it under cover to finish. Shell once the beans are hard enough that a fingernail leaves no dent.

One safety point, which is not optional

Raw lima beans contain linamarin, a cyanogenic glycoside. They are never eaten raw.

Boil them uncovered for around fifteen minutes and discard the water — the compound breaks down and the volatile product escapes, which is why the pan is left uncovered. Varieties grown in North America and Europe are bred for low levels and are entirely safe prepared this way.

Snap beans and peas can be eaten straight off the plant. Lima beans cannot. It is the one thing about this crop worth remembering before anything else.

Step by step

Time
P90D
Cost
10
You need
Lima bean seed, bush or pole type, Compost or well-rotted manure, Mulch
Tools
Soil thermometer, Trellis or poles for climbing types

  1. Wait for soil above 65 F

    Lima beans need warmer soil than green beans and rot in cold wet ground. Measure at two inches deep rather than guessing from the air temperature, and wait for a steady 65 to 70 F, usually two to three weeks after the last frost.

  2. Choose bush or pole to suit your season

    Bush types crop in 60 to 75 days and suit short summers. Pole types need 85 to 95 days but yield two to three times as much over a longer picking period.

  3. Prepare a sunny bed with moderate fertility

    Full sun, at least six hours. Work in compost but skip nitrogen fertiliser — beans fix their own, and excess nitrogen gives lush foliage and few pods.

  4. Put supports in before sowing

    Pole limas climb six to ten feet and need a trellis, tripod or netting in place first. Driving poles in afterwards damages roots.

  5. Sow one inch deep, directly in the ground

    Space bush types three to six inches apart in rows two feet apart, and pole types four to six inches apart along the support. Do not transplant — beans resent root disturbance.

  6. Water once at sowing, then sparingly until germination

    Soak the bed once and then leave it. Seed sitting in cold wet soil is the main cause of failure, and lima seed is particularly prone to rotting.

  7. Mulch once seedlings are a few inches tall

    Two inches of straw or compost conserves moisture, keeps soil temperature steady and suppresses weeds without disturbing shallow bean roots.

  8. Water deeply and consistently through flowering

    About an inch a week, more in heat. Water stress during flowering and pod set is the main cause of pods failing to fill, so keep it even rather than alternating drought and flood.

  9. Expect flower drop above 85 F

    Lima flowers abort in sustained heat and the plant resumes setting pods when it cools. Keep watering, mulch heavily, and do not pull a plant that has stalled in a heatwave.

  10. Harvest when pods are plump and still green

    Pick for shelling when the pods have filled out and feel firm, before they yellow. For dry beans, leave them on the plant until the pods are papery and rattle.

Common questions

When should you plant lima beans?

When the soil at two inches deep has reached a steady 65 to 70 °F, which is usually two to three weeks after your last frost date — later than green beans. Lima beans are the most cold-sensitive common bean and the seed rots readily in cool damp soil, so sowing early gains nothing and often costs the whole row. In short-season regions, choose a bush variety that matures in 60 to 75 days rather than trying to start pole types early.

What is the difference between bush and pole lima beans?

Bush limas grow two feet tall, need no support, and crop over a concentrated two to three weeks at 60 to 75 days from sowing. Pole limas climb six to ten feet, need a trellis, take 85 to 95 days, and then produce two to three times the yield over a much longer picking period. Bush types suit short summers and small beds; pole types are the better choice wherever the season is long enough to finish them.

Why are my lima beans flowering but not setting pods?

Most often heat. Lima flowers abort when temperatures stay above about 85 °F, especially with warm nights, and the plant simply resumes setting pods when conditions ease. The other common cause is water stress during flowering, which has the same effect. Excess nitrogen is the third, producing heavy foliage at the expense of pods. In all three cases the plant recovers, so keep watering and mulching rather than pulling it out.

How do you know when lima beans are ready to pick?

For fresh shelling beans, when the pods are plump and bulging with visible seed shapes but still green and firm — a pod that has started to yellow is past its best for shelling, though still perfectly good. For dry beans, leave the pods on the plant until they are brown, papery and rattle when shaken, then pull the plants and finish drying them under cover. Picking regularly keeps the plant producing.

Do lima beans need fertiliser?

Very little, and nitrogen is actively counterproductive. Like all legumes they fix their own nitrogen from the air through root bacteria, and a nitrogen-rich feed gives you a large leafy plant with few pods. Work compost into the bed before sowing and leave it at that; if a soil test shows low phosphorus or potassium, those are worth correcting, since both support flowering and pod fill.

Are raw lima beans poisonous?

Raw lima beans contain linamarin, a cyanogenic compound, and should always be cooked before eating. Boiling in an uncovered pan for about fifteen minutes destroys it, which is why lima beans are never eaten raw the way a snap pea might be. Varieties grown in North America and Europe are bred for low levels and commercially safe once cooked, but the rule is simple and absolute: cook them, uncovered, and discard the water.

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