Cold hardiness & minimum temperature

Is Summer savory (Satureja hortensis)cold hardy? Hardiness zone & min temp

Also called savoury, sarriette.

About Summer savory

Satureja hortensis · also called savoury, sarriette · herb

Summer savory is an annual Mediterranean herb with peppery thyme-like leaves used with beans and sausages. Quick from seed and tolerant of poor soil. Pet-safe in culinary amounts.

Summer savory (Satureja hortensis, Lamiaceae) is a bushy annual native to southern Europe, with a peppery aroma reminiscent of marjoram and thyme; it is the classic partner herb for beans.

Sow seed shallowly since light aids germination; flavor is strongest before flowering, and the fast-growing plant can be harvested within about two months of sowing.

Cold limit: USDA Grown as an annual in zones 3-11 · RHS H4 (15-26°C)

Sources: plants.ces.ncsu.edu, extension.illinois.edu

What summer savory's hardiness rating actually means

Hardiness works differently for summer savory: 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 H4 means: Hardy in an average winter across much of the temperate world. On the US scale that maps to USDA Grown as an annual in zones 3-11 — 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 summer savory 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 summer savory 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 summer savory can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Frost protection for borderline summer savory

Summer savory 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.

Summer savory hardiness — frequently asked questions

Is summer savory cold hardy?

Hardiness works differently for summer savory: 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. Summer savory is grown Grown as an annual in zones 3-11; you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature summer savory 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 summer savory?

Summer savory is rated USDA Grown as an annual in zones 3-11 and RHS H4 — Hardy in an average winter across much of the temperate world.

Can summer savory 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 summer savory 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.