Cold hardiness & minimum temperature

Is Tongue of Fire Bean (Phaseolus vulgaris 'Tongue of Fire')cold hardy? Hardiness zone & min temp

Also called Tongue of Fire bean, borlotti bean, speckled shell bean.

More about tongue of fire bean

About Tongue of Fire Bean

Phaseolus vulgaris 'Tongue of Fire' · also called Tongue of Fire bean, borlotti bean · edible

'Tongue of Fire' is an Italian borlotti-type bean grown mainly for its plump, cream-and-red flecked shelling beans, though young pods can be eaten as snaps. Available in bush and semi-runner forms, it needs full sun, warm soil and steady moisture. Beans are shelled fresh or dried for soups and stews.

Cold limit: USDA Warm-season annual in zones 3-11 (frost-tender) · RHS H2 (18-30°C)

Watch for — Seed rot in cold soil: Direct-sown seed rots in cold, wet ground; wait for soil above 16°C and sow into warm, moist soil.

What tongue of fire bean's hardiness rating actually means

Hardiness works differently for tongue of fire 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 H2 means: Tender — survives a frost-free greenhouse or a very mild, sheltered spot. On the US scale that maps to USDA Warm-season annual in zones 3-11 (frost-tender) — 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 tongue of fire 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 tongue of fire 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 tongue of fire bean can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H2 figure above.

Frost protection for borderline tongue of fire bean

Tongue of Fire 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.

Tongue of Fire Bean hardiness — frequently asked questions

Is tongue of fire bean cold hardy?

Hardiness works differently for tongue of fire 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. Tongue of Fire Bean is grown Warm-season annual in zones 3-11 (frost-tender); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature tongue of fire 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 tongue of fire bean?

Tongue of Fire Bean is rated USDA Warm-season annual in zones 3-11 (frost-tender) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can tongue of fire 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 tongue of fire 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.