Cold hardiness & minimum temperature

Is White Guinea Yam (Dioscorea rotundata)cold hardy? Hardiness zone & min temp

Also called White yam, Guinea yam, Puna yam.

More about white guinea yam

About White Guinea Yam

Dioscorea rotundata · also called White yam, Guinea yam · edible

White Guinea Yam is the most important yam species in West African agriculture, producing large, starchy white-fleshed tubers used in fufu, pounded yam, and boiling. A tropical climber requiring a long, hot growing season. Raw Dioscorea species contain dioscorine and saponins — caution for pets and raw human consumption.

Cold limit: USDA 10-12 · RHS H1a (tropical; no tolerance of cold or frost) (25-35°C)

What white guinea yam's hardiness rating actually means

Hardiness works differently for white guinea yam: 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 10-12 — 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 white guinea yam 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 white guinea yam 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 white guinea yam 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 white guinea yam

White Guinea Yam 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.

White Guinea Yam hardiness — frequently asked questions

Is white guinea yam cold hardy?

Hardiness works differently for white guinea yam: 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. White Guinea Yam is grown as an annual in USDA 10-12; you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature white guinea yam 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 white guinea yam?

White Guinea Yam is rated USDA 10-12 and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can white guinea yam 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 white guinea yam 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.