Cold hardiness & minimum temperature

Is Crown Prince Squash (Cucurbita maxima 'Crown Prince')cold hardy? Hardiness zone & min temp

Also called Crown Prince squash, Crown Prince pumpkin.

More about crown prince squash

About Crown Prince Squash

Cucurbita maxima 'Crown Prince' · also called Crown Prince squash, Crown Prince pumpkin · edible

Crown Prince is a prized blue-grey skinned winter squash with dense, sweet, nutty orange flesh and outstanding storage life. A vigorous trailing annual, it needs a long warm season, full sun and very rich soil. Fruits are cured after harvest and keep for months, making it a favourite for autumn and winter cooking.

Cold limit: USDA 3-11 (warm-season annual) · RHS H2 (18-30°C)

What crown prince squash's hardiness rating actually means

Hardiness works differently for crown prince squash: 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 3-11 (warm-season 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 crown prince squash 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 crown prince squash 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 crown prince squash 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 crown prince squash

Crown Prince Squash 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.

Crown Prince Squash hardiness — frequently asked questions

Is crown prince squash cold hardy?

Hardiness works differently for crown prince squash: 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. Crown Prince Squash is grown 3-11 (warm-season annual); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature crown prince squash 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 crown prince squash?

Crown Prince Squash is rated USDA 3-11 (warm-season annual) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can crown prince squash 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 crown prince squash 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.