Cold hardiness & minimum temperature

Is Bean (Phaseolus vulgaris)cold hardy? Hardiness zone & min temp

Also called green bean, French bean, snap bean.

About Bean

Phaseolus vulgaris · also called green bean, French bean · edible

Bean is a warm-season nitrogen-fixing legume that grows fast, sets pods within 50-60 days, and feeds the soil through symbiotic rhizobia. Bush and pole varieties share the same care. Pet-safe by ASPCA standards.

Phaseolus vulgaris was domesticated independently in Mesoamerica (Mexico/Guatemala) and the Andes (Peru/Ecuador) over 8,000 years ago from wild small-seeded ancestors, giving two distinct genepools; it is a frost-tender warm-season legume.

A tender warm-season annual with no frost tolerance; sensitive to cold, it must be planted after the last spring frost and grown through warm weather.

Cold limit: USDA Grown as an annual in zones 3-11 · RHS H1c (18-29°C)

Watch for — Yellow leaves: Cold wet soil, bean rust, or mosaic virus.

Sources: extension.umn.edu, extension.psu.edu, kew.org

What bean's hardiness rating actually means

Hardiness works differently for bean: 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 3-11 — 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 bean 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 bean 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 bean 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 bean

Bean 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.

Bean hardiness — frequently asked questions

Is bean cold hardy?

Hardiness works differently for bean: 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. Bean is grown Grown as an annual in zones 3-11; you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature bean 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 bean?

Bean is rated USDA Grown as an annual in zones 3-11 and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can bean 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 bean 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.