What does USDA hardiness zone 5b mean in Ohio?

Zone 5b means an average annual extreme minimum winter temperature of −15 to −10 °F — the standard USDA measure of which perennials survive winter. 1 location in Ohio fall in this zone. It does not set planting dates; see the frost calendar below for that.

When should I plant tomatoes in Ohio's zone 5b?

Using Sparta's frost dates (this page's median-season location): start seeds indoors about Mar 2 – Mar 16, then transplant outside about May 4 – May 11. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.

Does every location in Ohio's zone 5b have the same frost dates?

No — they do not all share a weather station, so frost dates vary by a week or more across the 1 locations listed (see the table above for each location's own dates).

USDA zone 5b in Ohio

−15 to −10 °F avg. annual extreme minimum · 1 location in this group · NOAA 1991–2020 normals

USDA plant hardiness zone 5b covers 1 location across Ohio (average annual extreme minimum −15 to −10 °F): Sparta, OH. Average last spring frost across this group ranges April 27 and growing seasons run 172 days — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Ohio location's own frost dates; the printable planting calendar uses Sparta, this group's median-season location.

USDA zone: 5b−15 to −10 °F
Last frost range: Apr 27avg, 32°F
First frost range: Oct 17avg, 32°F
Growing season range: 172days

Locations in this group

Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.

Own frost dates per location.
Location	Also covers	Nearest station	Last frost	First frost	Season (days)
Sparta *	—	Centerburg 2 Se	Apr 27	Oct 17	172

* Sparta is this group's median-season location — the calendar below is computed from its data.

Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.

Planting calendar (Sparta, representative)

Computed from Sparta's average frost dates — the median-season location in this Ohiozone 5b group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).

Crop

JanFebMarAprMayJunJulAugSepOctNovDec

Tomato

Pepper

Cucumber

Summer squash / zucchini

Start indoors
Plant out
Fall sowing
First harvest

Planting windows for Sparta (Ohio, zone 5b), this group's representative location.
Crop	Frost tolerance	Start indoors	Plant out	First harvest	Fall planting	Season fit
Tomato	Tender	Mar 2 – Mar 16	May 4 – May 11	Jul 3 – Jul 23	—	matures comfortably
Pepper	Very tender	Feb 16 – Mar 2	May 11 – May 18	Jul 10 – Aug 9	—	matures comfortably
Cucumber	Tender	Mar 30 – Apr 6	May 4 – May 11	Jun 23 – Jul 13	—	matures comfortably
Summer squash / zucchini	Tender	—	May 4 – May 11	Jun 18 – Jul 3	—	matures comfortably
Bush bean	Tender	—	May 4 – May 11	Jun 23 – Jul 3	Aug 18 – Aug 28	matures comfortably
Sweet corn	Tender	—	Apr 27 – May 11	Jun 26 – Jul 26	—	matures comfortably
Basil	Very tender	Mar 16 – Mar 30	May 4 – May 11	Jun 3 – Jun 18	—	matures comfortably
Lettuce	Half-hardy	Mar 16 – Mar 30	Mar 30 – Apr 13	May 14 – May 29	Aug 4 – Aug 19	matures comfortably
Pea	Hardy	—	Mar 16 – Mar 30	May 10 – May 25	Jul 25 – Aug 9	matures comfortably
Spinach	Hardy	—	Mar 16 – Mar 30	Apr 25 – May 5	Aug 14 – Aug 24	matures comfortably
Carrot	Half-hardy	—	Apr 6 – Apr 13	Jun 5 – Jun 25	Jul 15 – Aug 4	matures comfortably
Broccoli	Half-hardy	Mar 2 – Mar 16	Mar 30 – Apr 13	May 24 – Jun 13	Jul 20 – Aug 9	matures comfortably

Which crops fit this growing season

Using Sparta's own 172-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.

Frost & freeze dates (Sparta)

From NOAA's 1991–2020 Climate Normals at station USC00331404. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.

Freeze probabilities by temperature threshold (MM/DD, NOAA 1991–2020), Sparta.
Threshold	Last spring — avg	Last spring — 90%-safe	First fall — avg	First fall — 90%-safe	Season (days)
36°F	May 6	May 22	Oct 5	Oct 17	152
32°F (freeze)	Apr 27	May 13	Oct 17	Oct 30	172
28°F	Apr 15	Apr 30	Oct 28	Nov 10	194
24°F	Apr 3	Apr 18	Nov 8	Nov 24	218

Growing degree days

Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 1 locations is 2,967; Sparta's own reading is shown below.

Annual growing degree days for Sparta (°F·days, NOAA 1991–2020).
Model	°F·days	Used for
Base 50°F (warm-season)	2,967	standard warm-season base (tomato, corn, beans)
Base 40°F (cool-season)	5,166	cool-season crops (brassicas, greens)

Hardiness zone 5b in Ohio

Zone 5b means an average annual extreme minimum winter temperature of about −15 to −10 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Ohio spans 4 hardiness zones in this dataset — see all Ohio locations for the full range, including zones6a, 6b, 7a.

Explore zone 5b in other states at zone 5b, or see all USDA hardiness zones.

Frequently asked questions

What does USDA hardiness zone 5b mean in Ohio?: Zone 5b means an average annual extreme minimum winter temperature of −15 to −10 °F — the standard USDA measure of which perennials survive winter. 1 location in Ohio fall in this zone. It does not set planting dates; see the frost calendar below for that.
When should I plant tomatoes in Ohio's zone 5b?: Using Sparta's frost dates (this page's median-season location): start seeds indoors about Mar 2 – Mar 16, then transplant outside about May 4 – May 11. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
Does every location in Ohio's zone 5b have the same frost dates?: No — they do not all share a weather station, so frost dates vary by a week or more across the 1 locations listed (see the table above for each location's own dates).

Sources & method

Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.