Cold hardiness & minimum temperature

Is Mung Bean (Vigna radiata)cold hardy? Hardiness zone & min temp

Also called Mung Bean, Green Gram, Golden Gram, Moong.

More about mung bean

About Mung Bean

Vigna radiata · also called Mung Bean, Green Gram · edible

Mung bean is a fast-growing warm-season annual legume widely cultivated for its protein-rich seeds and edible sprouts. It fixes atmospheric nitrogen, improving soil fertility. Plants mature in 60–75 days and tolerate heat and moderate drought. Seeds are eaten whole, split as dal, or sprouted; young leaves are also edible.

Cold limit: USDA 9-11 (grown as annual in zones 4-8) · RHS H1b (20–35°C)

What mung bean's hardiness rating actually means

Hardiness works differently for mung 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 H1b means: Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season. On the US scale that maps to USDA 9-11 (grown as annual in zones 4-8) — 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 mung 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 mung 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 mung bean can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Frost protection for borderline mung bean

Mung 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.

Mung Bean hardiness — frequently asked questions

Is mung bean cold hardy?

Hardiness works differently for mung 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. Mung Bean is grown 9-11 (grown as annual in zones 4-8); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature mung 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 mung bean?

Mung Bean is rated USDA 9-11 (grown as annual in zones 4-8) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can mung 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 mung 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.