Cold hardiness & minimum temperature

Is Lima beans (Phaseolus lunatus)cold hardy? Hardiness zone & min temp

Also called butter beans, sieva beans, Madagascar beans.

About Lima beans

Phaseolus lunatus · also called butter beans, sieva beans · edible

Lima beans are warm-season legumes grown for flat or rounded starchy seeds. Bush and pole types are available; pole limas crop longer. Need a long warm season. Pet-safe when cooked; raw beans contain trace linamarin.

Lima beans, Phaseolus lunatus, are a separate species from common beans, native to the Americas and notably more heat-loving; tender warm-season annual.

Needs warmer soil, warmer weather and a longer season than common beans, so in short-season regions choose lower-heat, shorter-season varieties; available in both bush and pole habits.

Cold limit: USDA Grown as an annual in zones 4-11 · RHS H1c (greenhouse in UK) (21-29°C)

Watch for — Slow start: Cold soil; wait until soil is above 18°C.

Sources: extension.umn.edu, web.extension.illinois.edu

What lima beans's hardiness rating actually means

Hardiness works differently for lima beans: it is grown as a seasonal crop, not overwintered. The question is not "what zone" but "how long is your frost-free growing window". Its RHS rating of H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA Grown as an annual in zones 4-11 — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

As an annual crop, its "minimum temperature" is the first hard frost — that is the end of the plant's life, not a survivable low. Many types are also damaged by light frost (around 0 °C).

Concretely, for lima beans as it gets too cold:

Light frost (around 0 to −2 °C) damages or kills tender summer crops outright; cold-hardy types take a few degrees of frost.
The plant does not "survive winter" — its life cycle simply ends, by design, when frost arrives or it finishes cropping.
A surprise late spring frost can also kill young transplants set out too early, before the season even starts.

Can lima beans go outside or overwinter — and where?

Time it to your frost dates: sow or plant out after the last spring frost, and aim to harvest before the first autumn frost.
In short-season zones, start it indoors or under cover to stretch the effective growing window.
Hardier crops in this group can be sown for an autumn or overwintered harvest in mild zones — check the specific crop.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when lima beans can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Frost protection for borderline lima beans

Lima beans is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

Use fleece, cloches or a cold frame at each end of the season to dodge a borderline frost and add growing weeks.
Have row cover ready for an unexpected late spring or early autumn frost.
Know your local last- and first-frost dates and count back the crop’s days-to-maturity to schedule the sowing.

Lima beans hardiness — frequently asked questions

Is lima beans cold hardy?

Hardiness works differently for lima beans: it is grown as a seasonal crop, not overwintered. The question is not "what zone" but "how long is your frost-free growing window". A seasonal crop, not a perennial. Lima beans is grown Grown as an annual in zones 4-11; you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature lima beans can survive?

As an annual crop, its "minimum temperature" is the first hard frost — that is the end of the plant's life, not a survivable low. Many types are also damaged by light frost (around 0 °C).

What hardiness zone is lima beans?

Lima beans is rated USDA Grown as an annual in zones 4-11 and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can lima beans survive winter outside?

Time it to your frost dates: sow or plant out after the last spring frost, and aim to harvest before the first autumn frost. In short-season zones, start it indoors or under cover to stretch the effective growing window. Hardier crops in this group can be sown for an autumn or overwintered harvest in mild zones — check the specific crop.

How do I protect lima beans from frost?

Use fleece, cloches or a cold frame at each end of the season to dodge a borderline frost and add growing weeks. Have row cover ready for an unexpected late spring or early autumn frost. Know your local last- and first-frost dates and count back the crop’s days-to-maturity to schedule the sowing.