Cold hardiness & minimum temperature

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

Also called Tepary Bean, Desert Bean, Pavi.

More about tepary bean

About Tepary Bean

Phaseolus acutifolius · also called Tepary Bean, Desert Bean · edible

An ancient desert-adapted bean domesticated by Indigenous peoples of the Sonoran Desert over 5,000 years ago, producing small, nutritious seeds (white, buff, brown, or black) on compact, drought-hardy plants. Exceptionally heat- and drought-tolerant — outperforms common beans in arid conditions. Matures quickly in 60–80 days on minimal rainfall. An increasingly important heritage and climate-resilient crop.

Cold limit: USDA 7–12 (frost-tender annual) · RHS H1a (25–40 °C)

What tepary bean's hardiness rating actually means

Hardiness works differently for tepary 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 H1a means: Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever. On the US scale that maps to USDA 7–12 (frost-tender annual) — 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 tepary 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 tepary 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 tepary bean can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1a figure above.

Frost protection for borderline tepary bean

Tepary 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.

Tepary Bean hardiness — frequently asked questions

Is tepary bean cold hardy?

Hardiness works differently for tepary 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. Tepary Bean is grown 7–12 (frost-tender annual); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature tepary 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 tepary bean?

Tepary Bean is rated USDA 7–12 (frost-tender annual) and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can tepary 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 tepary 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.