Cold hardiness & minimum temperature

Is Winter Melon (Benincasa hispida)cold hardy? Hardiness zone & min temp

Also called Winter Melon, Wax Gourd, Ash Gourd, White Gourd, Chinese Preserving Melon, Fuzzy Gourd (immature).

More about winter melon

About Winter Melon

Benincasa hispida · also called Winter Melon, Wax Gourd · edible

Winter melon is a large cucurbit producing impressive waxy, barrel-shaped fruits that store for months — earning the name 'winter melon' despite being a summer crop. Widely used across East and South Asian cooking in soups and stir-fries, the mild, starchy flesh is harvested both young (fuzzy) and mature (waxy white coating). It needs heat, space, and a long season.

Cold limit: USDA 9–12 (warm-season annual in cooler zones) · RHS H1c (24–35°C)

Watch for — Insufficient heat or season length: Winter melon requires 120–180 days of warm weather to mature fully. In temperate climates, start indoors 4–6 weeks before last frost and use cloches or a polytunnel to extend the season. Fruits harvested immature will not store long.

What winter melon's hardiness rating actually means

Hardiness works differently for winter melon: 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 9–12 (warm-season annual in cooler zones) — 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 winter melon 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 winter melon 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 winter melon can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Frost protection for borderline winter melon

Winter Melon 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.

Winter Melon hardiness — frequently asked questions

Is winter melon cold hardy?

Hardiness works differently for winter melon: 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. Winter Melon is grown 9–12 (warm-season annual in cooler zones); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature winter melon 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 winter melon?

Winter Melon is rated USDA 9–12 (warm-season annual in cooler zones) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can winter melon 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 winter melon 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.