Cold hardiness & minimum temperature

Is Broad Bean (Vicia faba 'Aquadulce Claudia')cold hardy? Hardiness zone & min temp

Also called Aquadulce Claudia, broad bean, fava bean.

More about broad bean

About Broad Bean

Vicia faba 'Aquadulce Claudia' · also called Aquadulce Claudia, broad bean · edible

'Aquadulce Claudia' is a hardy broad bean famous for autumn sowing, overwintering as young plants for an early summer crop. Upright and sturdy, it bears long pods of large, mild beans. A cool-season legume, it tolerates frost far better than French beans and is among the earliest fresh vegetables of the year.

Cold limit: USDA 3-8 (cool-season annual; hardy young plants overwinter) · RHS H5 (5-22°C)

What broad bean's hardiness rating actually means

Hardiness works differently for broad 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 H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 3-8 (cool-season annual; hardy young plants overwinter) — 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 broad 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 broad 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 broad bean can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Frost protection for borderline broad bean

Broad 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.

Broad Bean hardiness — frequently asked questions

Is broad bean cold hardy?

Hardiness works differently for broad 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. Broad Bean is grown 3-8 (cool-season annual; hardy young plants overwinter); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature broad 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 broad bean?

Broad Bean is rated USDA 3-8 (cool-season annual; hardy young plants overwinter) and RHS H5 — Hardy in most of the UK and in cold winters.

Can broad 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 broad 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.